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Prevalence of smoking-proxy electronic inhaling system (SEIS)
use and its association with tobacco initiation in youths:
a systematic review
Prevalence of smoking-proxy electronic inhaling system (SEIS)
use and its association with tobacco initiation in youths:
a systematic review
Sze Lin Yoong1,2,3, Flora Tzelepis1,2,3, John Wiggers1,2,3, Christopher Oldmeadow1,3, Li Kheng Chai1, Christine Paul1,3, Melanie Kingsland1,2,3, Luke Wolfenden1,2,3
1. School of Medicine and Public Health, University of Newcastle, Callaghan, New South Wales 2308, Australia
2. Hunter New England Population Health, Hunter New England Local Health District, Wallsend, New South Wales 2287, Australia
3. Hunter Medical Research Institute, Lot 1, Kookaburra Circuit, New Lambton Heights, New South Wales 2305, Australia
Document prepared for the World Health Organization
Prevalence of smoking-proxy electronic inhaling system (SEIS)
use and its association with tobacco initiation in youths:
a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Contents
Acknowledgements 6
Executive summary 7 Background 7 Objectives 7 Methods 7 Results 8 Conclusions 10
1. Background 11
2. Objectives 13
3. Methods 14 3.1 Inclusion criteria 14 3.2 Search strategy 15 3.3 Screening and data extraction 16 3.4 Critical appraisal 16 3.5 Data synthesis 17 3.5.1 Objective 1 17 3.5.2 Objective 2 18
4. Results 19 4.1 Eligible studies and study characteristics 19 4.1.1 Objective 1 19 4.1.2 Objective 2 20 4.2 Risk of bias 34 4.2.1 Objective 1 34 4.2.2 Objective 2 34 4.3 Overall prevalence of SEIS use among young people (objective 1) 34 4.4 Prevalence among non-smokers (objective 1) 36
5 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.5 Prevalence among current smokers (objective 1) 37 4.6 Exploring heterogeneity (for objective 1) 37 4.7 Objective 2 38
5. Discussion and conclusion 40 5.1 Discussion 40 5.2 Conclusion 42
References 43
Annexes 49
6 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
AcknowledgementsThe authors would like to acknowledge Debbie Booth for running the database search and Christophe Lecathelinais and Alessandra Bisquera for statistical support.
Declaration of conflict of interestAll authors declare no conflict of interest.
7 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Executive summary
BackgroundTobacco smoking remains a leading cause of death and disability worldwide. E-cigarettes (referred to here as smoking-proxy electronic inhaling systems, or SEIS) are marketed as having the potential to aid smoking cessation among current smokers, but may also be associated with increased likelihood of initiating tobacco smoking for non-smokers. A number of studies have suggested an increasing trend in SEIS use among youths, particularly among non-tobacco smokers. A positive association between SEIS use and tobacco use has been consistently reported in cross-sectional studies. To better understand the potential impact of SEIS use by young people, a synthesis of evidence regarding the prevalence and trends of SEIS use among this group is required, as is a synthesis of longitudinal data on the association between SEIS and future tobacco cigarette use.
ObjectivesThe objectives of the study are as follows:
1. To describe among young people (aged 10–20 years) the population prevalence and trends in prevalence of smoking-proxy electronic inhaling system (SEIS) use overall and among non-smokers and current smokers by country and by sex.
2. To synthesize findings from longitudinal studies of SEIS use by young people (aged ≤ 20 years) and its association with initiation of tobacco cigarette use.
MethodsA systematic review of the peer-reviewed and grey literature was undertaken in December 2015. Studies were included for objective 1 if they described the prevalence of SEIS use in a general population sample of young people aged ≤ 20 years in a defined geographical region using census or probability sampling. Studies where participants were recruited based on a specific health condition or as members of particular socioeconomic groups were excluded. There were no restrictions regarding the location of study, peer review status or language. A sensitivity analysis was undertaken including studies that did not include probability sampling but sampled for representativeness.
8 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
For objective 2, studies were included if they used a prospective longitudinal cohort design and assessed the association between SEIS use in young people aged ≤ 20 years at baseline and later use of combustible tobacco products. There were no restrictions on study sampling or recruitment methods, location of the study, peer review status or language of publication.
A single-search strategy for both objectives was employed that encompassed electronic databases of peer-reviewed manuscripts, grey literature Google searches, hand searches of relevant reference lists and consultation with experts in the field. Screening and data extraction were undertaken by three reviewers for peer-reviewed research and one reviewer for grey literature.
For both objectives, data from included studies were combined using random effect meta-analyses. To provide estimates of the prevalence of SEIS use in the previous three years, pooled estimates of “ever use” or “use in last 30 days (‘current use’)” of SEIS are also reported from studies using data collected between 2013 and 2015. To describe trends in prevalence of SEIS use, changes in prevalence of “ever use” or “use in last 30 days” over time for all studies between 2008 and 2015 were pooled, and described narratively by country where multiple comparable prevalence estimates were available during this time. All analyses were repeated for both current and non-current cigarette smokers. This analysis was repeated in a sensitivity analysis including four additional studies that did not use probability sampling but had sampled to be representative of the population.
Results Included studiesObjective 1. Overall, 2281 abstracts were screened (2246 electronic databases, 19 reports from the Google search and 16 reports from expert contacts). From these, 135 full texts were obtained for full-text screening, of which 28 publications reporting findings from 35 studies (each study represents a single survey) were included. An additional four publications reporting on findings from six studies were included in the sensitivity analysis. All studies utilized self-reported questionnaires to assess SEIS use. Eight of 32 studies satisfied seven of 10 quality assessment criteria, 17 satisfied five or six criteria, and seven satisfied three or four criteria. None of the studies reported on the reliability of the measures employed.
Objective 2. Overall, 2281 articles were screened and 119 full texts were obtained for further screening, with three studies being included in the final meta-analysis. All studies were undertaken in the United States of America. None of the studies were classified as having a sample representative of the target population and one study had a small sample of SEIS users at baseline (n=16). For all studies it was unclear whether the self-reported methods for collecting data on SEIS use and subgroup characteristics were reliable.
9 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Overall prevalence of SEIS use among overall sample(a) Ever use. The pooled estimate of the prevalence of SEIS ever use from 20 studies conducted between 2013 and 2015 was 16.4% (95% CI: 12.5–20.6%). Prevalence of ever use was 17.4% (95% CI: 10.9–25%) among males (from 14 studies) and 14.3% (95% CI: 8.7–21%) among females (from 14 studies). In the sensitivity analyses (23 studies), the prevalence of ever use was 16.1% (95% CI: 12.6–20.0%) overall, 19.3% (95% CI: 12.5–27.1%) among males and 15.5% (95% CI: 9.9–22.2%) in females (13 studies).
With one exception (Italy), for all five countries where multiple comparable prevalence estimates were available between 2008 and 2015, the prevalence of ever use increased over time (New Zealand, Poland, Republic of Korea, United States).
(b) Current use. The pooled estimate of the prevalence of current SEIS use from 19 studies conducted between 2013 and 2015 was 5.6% (95% CI: 3.4–8.3%). The prevalence of current use was 6.3% (95% CI: 3.7–9.6%) among males and 4.3% (95% CI: 2.4–6.8%) in females (12 studies). In the sensitivity analyses with an additional five studies (24 studies), the prevalence of SEIS ever use was 5.5% (95% CI: 3.5–7.9%) overall, 7.4 % (95% CI: 4.5–10.8%) among males and 4.9% (95% CI: 2.8–7.4%) in females (13 studies).
In three of the five countries where multiple comparable estimates of prevalence were available between 2008 and 2015, prevalence of current use increased (Poland, United Kingdom, United States). The prevalence of current SEIS use decreased in Hungary between 2012 and 2013, while the prevalence remained stable in Italy.
Prevalence among non-smokers(a) Ever use. The pooled estimate of the prevalence of ever use among non-smokers from 13 studies conducted between 2013 and 2015 was 7.0% (95% CI: 5.1–9.3%). In the sensitivity analyses with an additional three studies, the prevalence of SEIS ever use was 6.4% (95% CI: 4.6–8.5%) among non-smokers.
Multiple estimates of prevalence over time in the United States indicated that ever use by non-smokers increased. In contrast, the prevalence of such use did not change in Italy.
(b) Current use. The pooled estimate of the prevalence of current SEIS use among non-smokers from nine studies conducted between 2013 and 2015 was 1.5% (95% CI: 0.3–3.5%). In the sensitivity analyses with an additional four studies (15 studies), the prevalence of SEIS ever use among non-smokers was 1.3% (95% CI: 0.4–2.8%).
Comparable estimates of prevalence of current use by non-smokers over time were available between 2008 and 2015 from three countries: Italy, Poland and the United States. In the United States, the prevalence of current use in non-smokers increased in both middle school- and high school-aged students between 2011 and 2014. In Poland, the prevalence of use increased, while in Italy prevalence was 0% across all periods of data collection.
10 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Prevalence among current smokers(a) Ever use. The pooled estimate of the prevalence of SEIS ever use among current tobacco smokers from 13 studies conducted between 2013 and 2015 was 54.7% (95% CI: 45.9–60.5%). In the sensitivity analyses with an additional two studies (15 studies), the prevalence of SEIS ever use was 53.2% (95% CI: 45.9 –60.5%) among current smokers.
In the United States, the prevalence of SEIS ever use among current tobacco smokers increased, while it remained stable in Italy.
(b) Current use. The pooled estimate of the prevalence of SEIS current use among current tobacco smokers from 10 studies conducted between 2013 and 2015 was 19.4% (95% CI: 8.3–33.5%). In the sensitivity analyses with an additional two studies (14 studies), the prevalence of SEIS ever use was 17.8% (95% CI: 8.8–28.9%).
Multiple comparable estimates of prevalence of SEIS use across 2008–2015 in Poland and the United States showed an increase in current use of SEIS among smokers. In Italy, prevalence remained stable.
Association between SEIS ever use and tobacco cigarette use Three studies conducted in the United States were included in the analysis, with each study indicating that non-tobacco-smoking young people who were SEIS users were significantly more likely to be tobacco smokers at follow-up. Pooled analysis of the studies indicated that SEIS smokers at baseline had an increased adjusted odds ratio (AOR 2.19; 95% CI: 1.46–3.3%; I2 = 59.7%) of being a tobacco cigarette user at follow-up.
ConclusionsThis systematic review and meta-analysis found substantial differences in prevalence and changes in prevalence of SEIS use by country. More than half of all young tobacco smokers in Canada, Ireland, New Zealand, the United Kingdom and the United States had ever used SEIS. Use of SEIS among young people was reportedly increasing in Poland and the United States but not in some other countries, for example Hungary and Italy. Pooled findings from two longitudinal studies indicated that the use of SEIS by non-smokers more than doubled the odds of tobacco smoking at follow-up.
Despite current low prevalence of SEIS use among non-smoking young people in most jurisdictions, the finding of a longitudinal association between SEIS use and subsequent tobacco use, and the increasing prevalence of SEIS use among non-smoking young people in some countries, supports the need for strategies to discourage SEIS uptake among non-smokers.
11 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
1. Background
Internationally, tobacco use is the leading cause of preventable death and disability (1). The 2013 Global Burden of Disease Study reported that tobacco use accounted for 6.1 million deaths and 143.5 million disability-adjusted life-years globally (2). While there is considerable between-country variation in the current prevalence of tobacco use, the global prevalence declined between 1980 and 2012 from 41.2% to 31.1% for men and 10.6% to 6.2% for women (3). Globally, the largest annualized rate of change over this period occurred among those aged 15–19 years, where the rate declined by 1.8% each year (3). Given the significant health and societal burden of tobacco use (2), comprehensive strategies to prevent initiation and assist cessation have been recommended (4).
There has been considerable debate about the potential role of e-cigarettes in addressing tobacco use, particularly among young people (5, 6). Electronic cigarettes (referred to here as smoking-proxy electronic inhaling systems, or SEIS) are battery-operated devices designed to deliver a solution as an aerosol (or “vapour”) typically made up of propylene glycol or glycerol (glycerine), nicotine, and flavouring agents, which is inhaled by users (7). The devices are designed to simulate the act of smoking tobacco cigarettes to allow the consumption of nicotine without the burning of tobacco. SEIS has been primarily marketed as an alternative to combustible tobacco, as an aid to reduce or cease tobacco smoking or a means of using nicotine in smoke-free environments (7). To date, the impact of SEIS in aiding smoking cessation is equivocal, with a recent Cochrane review reporting a small positive effect from only two randomized controlled trials (8). Concerns regarding the long-term safety of the use of SEIS however have led to at least 55 countries introducing legislation or bans prohibiting or restricting the sale of SEIS (9).
Since their introduction, the use of SEIS among young people has received considerable attention. A 2014 systematic review reported increasing use of SEIS among young people in countries such as Poland and the United States since 2011 (10). Findings from the review highlighted some differences in patterns of SEIS use among young people compared to older individuals, with a significantly greater proportion of adolescent
12 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
SEIS ever users reporting no previous use of tobacco cigarettes. Similarly, a national study in Poland reported that over 20% of adolescent SEIS users were non-tobacco smokers (11); and in some United States jurisdictions, SEIS use among adolescents exceeded traditional tobacco cigarette use (12). While a small proportion of young adults report using SEIS to aid cessation (13, 14), studies suggest that younger adults are more likely to use SEIS primarily for experimentation purposes (10, 13).
The increasing rate of SEIS use among young people generally and among non-smokers in particular has led to concerns that SEIS use and particularly experimentation by young people could lead to nicotine dependence into adulthood and subsequent tobacco initiation (15). The potential mechanisms driving this process are unknown, though a recent review proposed a number of hypothesized pathways that may account for the initial uptake of SEIS and the transition between SEIS experimentation and nicotine dependence (16). To date, however, such concerns that SEIS use may lead to tobacco uptake have primarily been examined via cross-sectional studies. These studies reported positive associations between SEIS use and tobacco smoking behaviour among youths who had not previously used tobacco (17–19). In the absence of longitudinal studies, such findings do not allow for the examination of causality and directionality (i.e. whether SEIS use leads to initiation of tobacco smoking).
A synthesis of the current prevalence and patterns of SEIS use among young smokers and non-smokers is needed to better understand the potential impacts of SEIS use on adolescent tobacco smoking behaviour. Further, a synthesis of longitudinal data regarding the association between SEIS and tobacco smoking by young people is needed to allow examination of the potential impact of SEIS use on subsequent tobacco smoking and other forms of combustible tobacco use. For the purpose of this systematic review, “young people” have been defined as those aged 10–20 years and “adolescents” have been defined as those aged 15–19 years, consistent with WHO definitions.
13 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
2. Objectives
The objectives of the study are as follows:
1. To describe among young people (aged ≤ 20 years) the population prevalence and trends in prevalence of smoking-proxy electronic inhaling system (SEIS) use overall and among non-smokers and current smokers by country, sex and SEIS type.
2. To synthesize findings from longitudinal studies of SEIS use by young people (aged ≤ 20 years) and initiation of tobacco cigarette use.
14 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
3. Methods
A systematic review of the peer-reviewed and grey literature was undertaken between August and December 2015. The review was conducted in accordance with the Cochrane Collaboration review methods and involved searching multiple electronic databases, using two independent reviewers, undertaking formal critical appraisal with the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data (20), and undertaking meta-analysis where appropriate.
3.1 Inclusion criteria Objective 1. For this objective, studies were included if they described the prevalence of SEIS use in the general population within a defined geographical region (such as province, state or country). To be eligible studies needed to employ census or probability sampling methods, and report SEIS use in young people with a mean age of between 10 and 20 years. For studies that included those aged over 20 years, the study was included if a subgroup analysis of SEIS use among those aged ≤ 20 years was reported. Studies reporting any measure of SEIS (e.g. self-reported, secondary (or proxy) reported or biochemical assessments) were included.
Studies using data from specialist panels (such as online research panels) or cohort studies that did not employ probability sampling procedures and recruitment procedures were excluded, regardless of whether population weights were applied to estimates of SEIS use. Probability sampling has been identified as an important requirement of quality prevalence studies (21). Studies where participants were recruited based on a pre-existing disease or condition (e.g. mental health, hospital), or on the basis of specific socioeconomic characteristics (e.g. located in a lower socioeconomic region) and disease characteristics (e.g. patients with cardiovascular disease), were also excluded. Finally, non-databased publications that did not present new data (e.g. commentaries and opinion pieces) were excluded. There were no other restrictions regarding the location of the study, peer review status or language of publication.
15 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Objective 2. For this objective, studies employing prospective longitudinal cohort designs that aimed to assess the association of SEIS use in young people and initiation of combustible tobacco products were included. Cross-sectional, case control and retrospective studies were excluded as they did not allow direct examination of causality, as were non-databased publications that did not present new data. To be eligible, longitudinal cohort studies needed to include non-smokers with a mean age of between 10 and 20 years at baseline and examine tobacco use at follow-up. Studies reporting any measure of SEIS use (e.g. self-reported, secondary (or proxy) reported or biochemical assessments) and that examined tobacco smoking use at follow-up were included. There were no other restrictions on study sampling or recruitment methods, location of the study, peer review status or the language of publication. No restrictions on sampling methods were employed for this objective as the primary aim was to assess association between baseline SEIS use and tobacco cigarette uptake.
3.2 Search strategyA single-search strategy was employed to identify relevant peer-reviewed and grey literature for both objectives. The search encompassed electronic databases of peer-reviewed manuscripts, Google searches, hand searches and consultation with experts in the field.
• Electronic databases. A systematic search of the electronic databases MEDLINE, EMBASE, PsycInfo, Cochrane and CINAHL was undertaken by an experienced academic librarian. Search terms for SEIS were based on those used in previous systematic reviews of SEIS use (8, 22). Broadly, the search terms included e-cig*, electronic nicotine*, electronic hookah* and e-hookah* as Medical Subject Headings (MeSH) terms. The full search string for each electronic database is provided in Annex 1.
• Google search. Searches were undertaken to identify potentially eligible reports, papers and conference abstracts for inclusion. The terms “electronic cigarette” and “ecigarette” were entered into separate Google.com searches. The results listed on the first 75 pages (750 hits) of each search were examined for relevant grey literature.
• Hand searches. Relevant references examining SEIS use in young people identified in the searches above were examined for potentially eligible studies for inclusion. The reference lists of all eligible studies were also screened for any additional studies potentially relevant to the objectives of this review.
• Experts in the field. Additional information about SEIS use in young people was sought from experts recommended by the Tobacco Unit of the World Health Organization and from selected authors who had published two or more relevant studies in the SEIS field. Experts were asked to identify any published or unpublished manuscripts (e.g. reports, papers, conference abstracts) or additional data relevant
16 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
to the report objectives. An email was sent to 15 experts on 31 August 2015. One respondent suggested an additional two experts be contacted and an email was sent to these experts on 11 September 2015. One respondent also contacted a further 13 experts on 13 September 2015. Given the rapid progress in the SEIS field, this process was repeated by sending another email to these experts on the 16 December 2015 asking whether they had any recent unpublished data that was relevant to this review. The experts were located in Australia, Canada, Germany, Italy, Romania, the United Kingdom and the United States.
3.3 Screening and data extractionEndNote version X6.0.1 software (Thomson Reuters, PA, United States) was used to manage study inclusion and filter duplicate studies. SLY and LW1 screened all databased results and FT screened all citations from the grey literature search. The full texts of all potentially eligible studies were obtained and study eligibility was determined based on assessment of the full text. Where eligibility was unclear, authors were contacted to request additional information. “Google translate” was used to assist with assessing the eligibility of non-English language manuscripts (n=25), which were all excluded prior to the full-text screening.
SLY, LW or LKC extracted the following information for all included studies in objective 1: author name, publication year, country of study, sample size, participant age range and sex, year of data collection, data collection modality, sampling procedures, measure of SEIS use, type of SEIS used (e.g. e-hookah), prevalence of SEIS use by sex, and prevalence of SEIS use among smokers and non-smokers (including n, percentages and 95% confidence intervals, where available) (see Annex 2). A consensus process was used to resolve any differences in extraction. Data for total denominators were also obtained from other sources (e.g. other references or raw datasets) to allow for inclusion in the meta-analysis. For objective 2, author last name, year of publication, participant characteristics (mean age), study design, country, sampling frame, outcomes, data collection modality, analyses, odds ratio and 95% CI, covariates adjusted for and follow-up time points were extracted by SLY. For the included studies, other supporting publications or reports (for example protocols, full descriptions of study methods from government websites) were also sought to obtain relevant information where the data from the primary study were absent or unclear. Data extraction was undertaken using prepiloted data extraction forms developed for the purpose of the study.
3.4 Critical appraisalTwo reviewers (MK and FT) independently undertook critical appraisal using the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data (20). The instrument contains 10 items examining the following study characteristics: sample representativeness, sampling methods, adequacy of sample size, participant and setting descriptions, coverage of sample, objectivity of criteria, reliability of measurement,
1 Authors’ initials: see list of authors.
17 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
appropriateness of statistical analysis, confounding factors identified and accounted for, and objective classification of subpopulations (Yes; No; Unclear; and N/A). This tool has been found to have face validity and to be acceptable and easy to use (23).
For objective 2, in addition to completing the Joanna Briggs Institute critical appraisal checklist for studies reporting prevalence data assessment (20), the reviewers also examined the following study characteristics for the longitudinal studies: whether the outcome of interest (tobacco smoking) was absent at baseline, whether known confounders were adjusted for in the analysis, and whether there was appropriate treatment of missing data. For both objectives, where discrepancies in coding emerged between reviewers, inconsistent ratings were discussed between the reviewers until consensus was reached.
3.5 Data synthesisAll analyses were undertaken using Stata version 14 software (StataCorp, College Station, TX, United States) and the Metaprop and Metareg packages. For both objectives, main findings from the individual studies were also described narratively where relevant.
3.5.1 Objective 1Data from included studies were combined using a random effect meta-analysis, weighted according to the inverse variance method. The Freeman-Tukey double arcsine transformation of prevalences was also used to allow for studies with prevalences that were close to zero. Exact 95% confidence intervals for the individual studies were computed.
Pooled estimates of SEIS ever use, and use in last 30 days (“current use”), were reported as stratified by country and sex (where available). Studies that included occasional users were pooled with ever users; and studies that reported regular use were pooled with last 30 days (or current use). Pooled estimates of ever and current SEIS use among non-smokers and smokers were also reported as stratified by country. Estimates of non-smokers included those not currently smoking (including ex-smokers) where available, and estimates of smokers included those reporting using any tobacco (including experimenters and occasional or current users) where available. Where prevalence of SEIS use by current smokers and non-smokers was not specifically reported, estimates of use were calculated using the following information provided in the original publications: number in total sample, prevalence of SEIS users, prevalence of smokers, and prevalence of concurrent SEIS and tobacco users. Estimates of regular/occasional use were available for four studies (24–27). Where individual studies provided weighted and unweighted measures of SEIS prevalence, weighted estimates were used. Pooled estimates of prevalence are reported as an absolute percentage with 95% confidence intervals. Heterogeneity was assessed using the I-squared statistic and reported for each point estimate, together with the chi-square statistic from the likelihood ratio test comparing the random and fixed effects model, the estimated between-study variance and its test of significance. For pooled estimates of current or ever use, this analysis
18 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
was repeated in a sensitivity analysis, including studies that did not use probability sampling but attempted to sample in a way that was representative of the population.
To explore additional potential causes of heterogeneity, an exploratory meta-regression was performed with prevalence of ever and current SEIS use among young people overall and by smokers and non-smokers. Covariates included in this analysis included year of data collection, age, sex and country policies regarding the availability and marketing of SEIS to adolescents (classed as consumer product (no regulation), minimum age of purchase overall or banned overall), and MPOWER scores for 2014. Classification for SEIS regulation was made based on a previously published review examining SEIS policy internationally (9). MPOWER scores (out of 100) for countries included in the review were provided by a representative from the World Health Organization. MPOWER scores were introduced following the WHO Framework Convention on Tobacco Control, and are calculated based on six measures that are considered central to tobacco control policies: taxes and pricing; advertising, promotion and sponsorship; protection against second-hand smoke; public warnings against the dangers of tobacco smoking; providing cessation support to those intending to quit; and monitoring policies (1). The multivariable model that explained the most between-study variance was reported.
3.5.2 Objective 2To assess whether use of SEIS at baseline was associated with cigarette use at follow-up, a random effects meta-analysis was undertaken with adjusted log odds ratios. The pooled estimates of the odds ratio with 95% confidence intervals were reported.
19 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4. Results
4.1 Eligible studies and study characteristics 4.1.1 Objective 1Overall, 2281 abstracts were obtained and screened (2246 electronic databases; 19 reports from the Google search and 16 reports from expert contacts). From these, 135 full texts where eligibility was unclear were obtained for full-text screening. Of these, 28 publications that reported findings from 35 studies (each study represents a single survey) were included in the final meta-analyses for at least one of the outcomes. Of those included in the full-text screening, studies were excluded because they examined SEIS use only in individuals aged > 20 (n=55), did not report on prevalence of SEIS use (n=4), did not use probability sampling (n=4), did not sample to be representative of the region (n=14), were not empirical studies (n=12), or included findings previously reported in other published papers (n=18) (Figure A4.1)2. The four studies that described population prevalence but did not use probability sampling were included as part of a sensitivity analysis.
The included publications were conducted in 11 high-income countries: the United States (national and subnational) (n=11) (12, 19, 28–36), Republic of Korea (n=2) (37, 38), New Zealand (n=2) (26, 39), United Kingdom (Scotland and Wales) (n=2) (27, 40), Poland (n=2) (11, 41), Hungary (n=1) (42), Canada (n=2) (43, 44), Hong Kong Special Administrative Region (n=1) (17), France (n=1) (45), Ireland (n=1) (24), Italy (n=1) (25), Iceland (n=1) (46) and Greece (n=1) (47). These studies were conducted between 2008 (37) and 2015 (25), and sample size ranged from 99 (39) to 75 643 (38). Two studies included both young people and adults as part of their sample but presented findings separately for young people (n=99 and n=160–163) (25, 26). All studies reported estimates for young people under 20. All studies utilized self-reported questionnaires completed by participants administered via paper and pencil (n=23) (11, 12, 17, 19, 24, 27–33, 36, 37, 39–42, 44–47), web (n=2) (38, 48), telephone (n=1) (43) or face to face (n=2) (25, 26). Studies either assessed ever use of SEIS (n=23) (11, 24–31, 33, 35–41,
2 Note: all figures are contained within Annex 4.
20 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
43–48) or use in past 30 days (“current use”) (n=21) (11, 12, 17, 24–33, 35, 36, 38, 40–43, 47). Four publications also reported regular or occasional use (see Annex 3 for measures) (24–27). Dutra and Glantz (19) reported on the same dataset as Corey et al. (31) (United States National Youth Tobacco Survey 2012 and 2013), but presented findings by smokers and non-smokers. Overall prevalence was included in the meta-analysis only once for these studies. None of the studies examined types of SEIS used. Seventeen publications (reporting on 22 studies) (11, 17, 19, 24, 25, 27, 30, 33, 37–42, 46, 47) reported prevalence of SEIS use by current smokers and non-smokers, but none provided these estimates by sex. An additional four studies conducted in Switzerland (49) and the United Kingdom (50–52) were included in the sensitivity analyses. Study characteristics are reported in Table 1.
4.1.2 Objective 2For objective 2, 2281 articles were screened and 119 full texts were obtained for further screening, with three studies meeting the eligibility criteria and included in the review (Figure A4.2) (54–56). Studies included in the full-text screening were excluded primarily because they were cross-sectional studies, commentaries or reviews (n=79). Other reasons for exclusion included not examining SEIS use (n=5), conducted with adults (n=5), conference abstract of published data (n=1), and did not examine association with tobacco/cigarette smoking (n=26) (Figure A4.2). All included studies were undertaken in the United States and quantified participants’ SEIS ever use via a single question. The mean age for two studies was 14 years and the other was 20 years. Study characteristics are reported in Table 2.
21 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Tabl
e 1.
Stu
dy c
hara
cter
istic
s of
all
incl
uded
cro
ss-s
ectio
nal s
tudi
es e
xam
inin
g pr
eval
ence
of S
EIS
use
amon
g yo
ung
peop
le (o
bjec
tive
1)N
ote:
Eas
twoo
d, 2
015
(50)
, For
d, 2
016
(52)
, Sur
ís, 2
015
(49)
, and
Wes
t, 20
12 (5
3) (fi
rst a
utho
rs’ nam
es) w
ere includ
ed in
sen
sitiv
ity ana
lyses an
d no
t main an
alyses.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Alas
ka
Dep
artm
ent o
f H
ealt
h an
d So
cial
Se
rvic
es, 2
015
(35)
Uni
ted
Stat
es
(Ala
ska)
2015
Yout
h Ri
sk
Beha
viou
r Sur
vey
1 41
8A
natio
nally
repr
esen
tativ
e sa
mpl
e of
pub
lic h
igh
scho
ols
in A
lask
a w
as
scientifically selected
F: 5
0%
M: 5
0%
grad
es
9–12
Que
stio
nnai
re,
pen
and
pape
r
Anan
d, 2
015
(28)
U
nite
d St
ates
(C
alifo
rnia
)
2013
Hig
h Sc
hool
Q
uest
ionn
aire
m
odel
led
afte
r M
onito
ring
the
Futu
re
2 76
9Al
l thr
ee h
igh
scho
ols
in n
orth
Cal
iforn
ia w
ere
incl
uded
in th
e st
udy
F: 5
1.1%
M: 48.9%
grad
es
9–12
Que
stio
nnai
re,
pen
and
pape
r
Arrazola, 201
4 (2
9)
Uni
ted
Stat
es20
13N
atio
nal Y
outh
To
bacc
o Su
rvey
(N
YTS)
18 406
; 18
7 sc
hool
s (74.8%
)
A th
ree-
stag
e cl
uste
r sa
mpl
ing
proc
edur
e to
gen
erat
e a
cros
s-se
ctio
nal,
natio
nally
re
pres
enta
tive
sam
ple
of
stud
ents
in g
rade
s 6–
12
from
all
stat
es a
nd th
e D
istr
ict o
f Col
umbi
a. A
stratifi
ed cluster sam
ple,
desi
gned
to o
vers
ampl
e no
n-H
ispa
nic
blac
k an
d H
ispa
nic
stud
ents
, was
em
ploy
ed
F: 49%
M: 5
1%
11–14
ye
ars
(mid
dle
scho
ols)
, 15
–18
ye
ars
(hig
h sc
hool
s)
Que
stio
nnai
re,
pen
and
pape
r
22 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Arra
zola
, 201
5 (1
2)
Uni
ted
Stat
es20
14N
atio
nal Y
outh
To
bacc
o Su
rvey
(N
YTS)
10 419
m
iddl
e sc
hool
st
uden
ts,
11 459
hi
gh
scho
ol
stud
ents
See Arrazola 201
4 N
ot
repo
rted
11–14
ye
ars
(mid
dle
scho
ols)
, 15
–18
ye
ars
(hig
h sc
hool
s)
Que
stio
nnai
re,
pen
and
pape
r
Babi
neau
, 201
5 (2
4)
Irel
and
2014
2014
You
th
Perc
eptio
n of
Pl
ain
Pack
agin
g St
udy,
a na
tiona
lly
repr
esen
tativ
e sc
hool
-bas
ed
survey of 1
6–17
-ye
ar o
lds
821
A re
pres
enta
tive
sam
ple
of s
econ
dary
sch
ools
from
ar
ound
the
coun
try
was
se
lect
ed fo
r par
ticip
atio
n an
d stratifi
ed based
on
loca
tion,
sch
ool t
ype
and
size
F: 5
0.2%
M: 49.8%
16–17
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
Barn
ett,
2015
(30)
U
nite
d St
ates
(F
lorid
a)
2013
2013
Flo
rida
Yout
h To
bacc
o Su
rvey
12 615
st
uden
ts
from
172
sc
hool
s
The
FYTS
use
d a
two-
stag
e cl
uste
r pro
babi
lity
sam
ple
desi
gn to
obt
ain
a ra
ndom
sam
ple
of p
ublic
m
iddl
e an
d hi
gh s
choo
ls
F: 49%
M: 5
1%
grad
es
6–12
Que
stio
nnai
re,
pen
and
pape
r
Cho,
201
1 (3
7)
Repu
blic
of
Kore
a20
0820
08 Health
Prom
otio
n Fu
nd P
roje
ct in
Re
publ
ic o
f Kor
ea
4 34
1A
clus
ter p
roba
bilit
y sa
mpl
e de
sign
was
use
d.
To d
istr
ibut
e th
e di
stric
ts
even
ly, five schoo
ls were
chos
en b
ased
on
thei
r ge
ogra
phic
al lo
catio
ns
F: 5
1.2%
M: 48.8%
13–
19
year
sQ
uest
ionn
aire
, pe
n an
d pa
per
23 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Corey, 20
14 (3
1)
Uni
ted
Stat
es20
11, 2
012
Nat
iona
l You
th
Toba
cco
Surv
ey
(NYT
S)
18 866
(2
011)
,a 24
658
(2
012)
see Arrazola 201
4(2
011)
F: 49.4%
M: 5
0.6%
(201
2)
F: 48.9%
M: 5
1.1%
11–14
ye
ars
(mid
dle
scho
ols)
, 15
–18
ye
ars
(hig
h sc
hool
s)
Que
stio
nnai
re,
pen
and
pape
r
Dau
tzen
berg
, 20
13 (4
5)
Fran
ce
(Par
is)
2012
Annu
al s
urve
y co
nduc
ted
by
Paris
San
Tab
ac
2 51
9Su
rvey
was
con
duct
ed o
n 2%
of s
tude
nts
rand
omly
se
lect
ed b
y cl
ass
and
prov
ided
a re
pres
enta
tive
sample of th
e 18
8 00
0 sc
hool
chi
ldre
n of
Par
is
F: 49.5%
M: 5
0.5%
12–
19
year
sQ
uest
ionn
aire
, pe
n an
d pa
per
Dutra, 201
4 (1
9)
Uni
ted
Stat
es20
11, 2
012
Nat
iona
l You
th
Toba
cco
Surv
ey
(NYT
S)
17 353
(2
011)
, 22
529
(2
012)
See Arrazola 201
4F: 49.4%
M: 5
0.6%
Grad
es
6–12
Que
stio
nnai
re,
pen
and
pape
r
24 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
East
woo
d, 2
015
(50)
U
nite
d Ki
ngdo
m
(Eng
land
)
2013
, 201
4Yo
uGov
20
13/201
42 17
7 (2
013)
, 2 06
8 (201
4)
Individu
als ag
ed 16–
18
wer
e sa
mpl
ed d
irect
ly
from
You
Gov’s
onl
ine
pane
l of p
eopl
e w
ho h
ad
prov
ided
con
sent
to b
e co
ntac
ted
and
wer
e se
nt
an e
mai
l inv
itatio
n to
take
pa
rt. I
ndiv
idua
ls a
ged
11–
15 w
ere
recr
uite
d vi
a an
em
ail t
o pa
rent
s or
lega
l gu
ardi
ans
from
the
YouG
ov
pane
l, w
hich
ask
ed th
em
to re
ad th
e in
form
atio
n ab
out t
he s
urve
y, an
d th
en
pass
the
surv
ey o
ver t
o th
eir c
hild
if th
ey a
nd th
eir
child
agr
eed
to ta
ke p
art.
Thos
e gi
ving
con
sent
wer
e as
ked
to fo
llow
a li
nk to
th
e su
rvey
onl
ine
(201
3)
F: 5
2.3%
M: 47.7%
(201
4)
F: 5
1.1%
M: 48.9%
11–18
ye
ars
Web
-bas
ed
ques
tionn
aire
Ford
, 201
6 (5
2)
Uni
ted
King
dom
2014
Yout
h To
bacc
o Po
licy
Surv
ey
(YTP
S)
1 20
5U
sing
rand
om lo
catio
n qu
ota
sam
plin
g,
part
icip
ants
wer
e dr
awn
from
92
elec
tora
l w
ards
acr
oss
the
Uni
ted
King
dom, stratified
by
Governmen
t Office Reg
ion
and A Classification
Of R
esid
entia
l N
eigh
bour
hood
s (A
CORN
)b
F: 5
0%
M: 5
0%
11–
16
year
sFa
ce to
face
25 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Fotio
u, 2
015
(47)
Gr
eece
2014
2014
Health
Beha
viou
r in
Scho
ol-a
ged
Child
ren
Surv
ey
1 32
0A
natio
nwid
e pr
obab
ility
sa
mpl
e of
stu
dent
s. Sa
mpl
ing
units
wer
e sc
hool
cla
sses
dra
wn
by m
ultis
tage
clu
ster
ed
prob
abili
ty s
ampl
ing
from
th
e M
inis
try
of E
duca
tion’
s co
mpl
ete
listin
g. S
ampl
ing
was
pro
port
iona
l acr
oss
scho
ol ty
pes
and
regi
ons
F: 51.7%
M: 48.3%
15 y
ears
Que
stio
nnai
re,
pen
and
pape
r
Gallu
s, 20
13 (2
5)
Ital
y20
13, 201
4,
2015
Unspe
cifie
dc16
3 (2
013)
, 15
3 (201
4),
160
(201
5)
An overall sample of 3 000
individu
als ag
ed ≥ 15
year
s re
pres
enta
tive
of th
e ge
nera
l Ita
lian
popu
latio
n ag
ed 1
5 ye
ars
and
over
w
as s
urve
yed
(201
3,
2014
)
F: 46%
M: 54%
(201
5)
F: 48%
M: 5
2%
15–
19
year
sc
Face
to fa
ce
Goni
ewic
z, 20
12
(41)
Po
land
2010
–20
11Unspe
cifie
d 13
787
from
144
sc
hool
s an
d 32
un
iver
sitie
s
A three-stag
e stratifi
ed
clus
ter s
ampl
ing
proc
edur
e, w
here
by
scho
ols
and
univ
ersi
ties
wer
e tr
eate
d as
the
prim
ary
unit,
was
use
d.
Regi
ons
with
a p
opul
atio
n of ≤ 20 00
0 were exclud
ed
F: 54.8%
M: 45.2%
15–
19
year
sQ
uest
ionn
aire
, pe
n an
d pa
per
Goniew
icz, 20
14
(11)
Po
land
2013
–20
14Unspe
cifie
d 1 97
0 Se
e Go
niew
icz, 20
12; o
nly
stud
ents
recr
uite
d fr
om 2
1 sc
hool
s ac
ross
two
regi
ons
in P
olan
d w
ere
incl
uded
in
the 20
14 com
paris
on
Not
re
port
ed15
–19
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
26 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Ham
ilton
, 201
5 (4
4)
Cana
da
(Ont
ario
)20
1320
13 O
ntar
io
Stud
ent D
rug
Use
an
d H
ealt
h Su
rvey
2 83
2Stratifi
ed tw
o-stag
e (s
choo
l, cl
ass)
, tw
o cl
uste
r de
sign
, stude
nts from
42
boards, 198
schoo
ls and
67
1 classroo
ms. Only ha
lf of
the
sam
ple
com
plet
ed
the
e-ci
g pa
rt (g
rade
s 9–
12)
F: 48%
M: 5
2%
grad
es
9–12
Que
stio
nnai
re,
pen
and
pape
r
Hun
garia
n Fo
cal
Poin
t for
Tob
acco
Co
ntro
l (42
)
Hun
gary
2012
, 201
3Gl
obal
You
th
Toba
cco
Surv
ey2 32
5 (201
2);
4 10
8 (2
013)
A tw
o-stag
e stratifi
ed
clus
ter s
ampl
e de
sign
th
at p
rodu
ced
sam
ples
of
stud
ents in
grade
s 7, 8 or 9
aged
13–
15 y
ears
from
all
Hun
garia
n sc
hool
s
Not
re
port
ed13
–15
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
John
ston
, 201
5 (3
2)
Uni
ted
Stat
es20
14M
onito
ring
the
Futu
re: n
atio
nal
surv
ey re
sult
on
drug
use
41 600
A th
ree-
stag
e ra
ndom
sa
mpl
ing
proc
edur
e us
ed
to s
ecur
e th
e na
tionw
ide
sam
ple
of s
tude
nts
at
each grade
level from 420
sc
hool
s
Not
re
port
ed13
–18
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
Kris
tjans
son,
201
5 (4
6)
Icel
and
2015
Yout
h in
Icel
and
Surv
ey3 47
7M
etho
ds s
imila
r to
the
MTF
sur
vey
and
Euro
pean
Sc
hool
Pro
ject
. The
You
th
in Ic
elan
d su
rvey
s ar
e ad
min
iste
red
to a
ll 10
th
grad
e st
uden
ts (a
ges
15–
16 y
ears
) in
Icel
and
by th
e Ic
elan
dic
Cent
re fo
r Soc
ial
Rese
arch
and
Ana
lysi
s at
Re
ykja
vik
Uni
vers
ity
F: 50.8%
M: 49.2%
15–
16
year
sQ
uest
ionn
aire
, pe
n an
d pa
per
27 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Lee, 201
4 (3
8)
Repu
blic
of
Kore
a20
1120
11 K
orea
n Yo
uth
Risk
Be
havi
our W
eb
Surv
ey
75 643
A stratifi
ed m
ultis
tage
cl
uste
r sam
plin
g m
etho
d w
as u
sed.
The
sur
vey
was
ad
ministered to 2 400
cl
assr
oom
s (s
econ
dary
sa
mpl
ing
units
) con
sist
ing
of a
ll st
uden
ts in
thre
e cl
asse
s fr
om e
ach
of th
e 40
0 middle an
d 40
0 high
sc
hool
s (p
rimar
y sa
mpl
ing
units
) fro
m 1
29 s
trat
a
F: 47.3%
M: 52.7%
13–18
ye
ars
Web
-bas
ed
ques
tionn
aire
Li, 2
015
(26)
N
ew
Zeal
and
2014
Hea
lth
and
Life
styl
es S
urve
y (H
LS)
2 59
4 bu
t on
ly 3.8%
(n=9
9)
wer
e 15
–17
ye
ars
A multis
tage
, stratified
, cl
uste
red
and
rand
om
prob
abili
ty s
ampl
ing
met
hod,
incl
udin
g an
oversample of M
āori an
d Pa
cific peo
ples. In 20
14,
New
Zea
land
201
3 Ce
nsus
m
esh
bloc
ks (i
.e.,
the
smal
lest
geo
grap
hica
l un
its fo
r whi
ch th
e Ce
nsus
da
ta a
re a
vaila
ble)
wer
e us
ed
F: 5
2.1%
M: 47.9%
15–17
ye
ars
Face
to fa
ce
Mon
tana
Office of
Publ
ic In
stru
ctio
n,
2015
(36)
Uni
ted
Stat
es
(Mon
tana
)
2015
Mon
tana
You
th
Beha
vior
al R
isk
Fact
or
4 48
6 st
uden
ts
from
49
scho
ols
(78%
)
All p
ublic
sch
ools
in
Mon
tana
with
stu
dent
s in
gr
ades
9 th
roug
h 12
wer
e el
igib
le to
be
sele
cted
for
incl
usio
n in
the
sam
ple.
Fi
fty-
four
sch
ools
wer
e ra
ndom
ly s
elec
ted
with
pr
obab
ility
pro
port
iona
l to
enro
lmen
t
F: 51.8%
M: 48.2%
grad
es
9–12
Que
stio
nnai
re,
pen
and
pape
r
28 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Moo
re, 2
015
(27)
U
nite
d Ki
ngdo
m
(Wal
es)
2014
The
Child
Ex
posu
re to
To
bacc
o Sm
oke
(CH
ETS)
sur
vey
unde
rtak
en in
W
ales
(CH
ETS
Wal
es 2
) and
the 20
14 W
elsh
Hea
lth
Beha
viou
r in
Sch
ool-
aged
Ch
ildre
n (H
BSC)
Su
rvey
(HBS
C W
ales
)
1 49
5 (C
HET
S),
8 95
0 (H
BSC
Wal
es)
CHET
S W
ales
2 s
ampl
ed
from
75 prim
ary scho
ols.
Stat
e-m
aint
aine
d sc
hool
s w
ith y
ear 6
stu
dent
s w
ere
stratifi
ed according
to
high
/low
free
sch
ool m
eal
entit
lem
ent,
and
loca
l ed
ucat
ion
auth
ority
HBS
C W
ales
sam
pled
from
82
secon
dary schoo
ls.
All m
aint
aine
d an
d in
depe
nden
t sec
onda
ry
scho
ols
in W
ales
wer
e stratifi
ed by local a
utho
rity
and
elig
ibili
ty fo
r fre
e sc
hool
mea
ls
(CH
ETS)
F: 5
0.2%
M: 49.8%
(HBS
C W
ales
)
F: 5
0.1%
M: 49.9%
10–
11
year
s (C
HET
S),
11–
16
year
s (H
BSC
Wal
es)
Que
stio
nnai
re,
pen
and
pape
r
NH
S N
atio
nal
Serv
ices
Sco
tlan
d,
2014
(40)
Uni
ted
King
dom
(S
cotl
and)
2013
, 201
4Sc
ottis
h Sc
hool
s Ad
oles
cent
Li
fest
yle
and
Subs
tanc
e U
se
Surv
ey (S
ALSU
S)
33 685
The
surv
ey s
ampl
ed p
upils
in
hig
h sc
hool
(yea
rs
2 an
d 4) in
Scotlan
d.
All l
ocal
aut
horit
y an
d in
depe
nden
tly
fund
ed
scho
ols
with
pup
ils in
the
targ
et a
ge g
roup
s w
ere
elig
ible
for i
nclu
sion
in th
e su
rvey
, with
the
exce
ptio
n of
sch
ools
for c
hild
ren
with
spe
cial
edu
catio
nal
need
s
F: 5
0%
M: 5
0%
13, 1
5 ye
ars
Que
stio
nnai
re,
pen
and
pape
r
29 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Pepp
er, 2
013
(34)
U
nite
d St
ates
2011
Know
ledg
e N
etw
orks
Kn
owle
dge
Pane
l
228
A su
rvey
com
pany
co
nstr
ucte
d a
natio
nal
pane
l of U
nite
d St
ates
ho
useh
olds
by
usin
g pr
obab
ility
sam
plin
g.
The
surv
ey c
ompa
ny
then
rand
omly
sam
pled
pa
nel m
embe
rs w
ho w
ere
pare
nts
with
son
s ag
ed
11–17
years. Paren
ts who
co
nsen
ted
in 2
010
to W
ave
1 w
ere
reco
ntac
ted
in
Wav
e 2,
whe
re th
eir s
ons
wer
e in
vite
d to
par
ticip
ate
F: 0
%
M: 1
00%
12–18
ye
ars
Web
-bas
ed
ques
tionn
aire
Port
er, 2
015
(33)
U
nite
d St
ates
(F
lorid
a)
2011
, 201
2,
2013
, 201
4D
ata
are
from
the
annu
al 2
011–
2014
Florid
a Yo
uth
Toba
cco
Surv
ey (F
YTS)
12 208
(2
011)
,d 75
428
(2
012)
, 69
923
(201
4)
See
Barn
ett 2
015
F: 49.6%
M: 50.4%
grad
es
6–12
Que
stio
nnai
re,
pen
and
pape
r
Reid
, 201
5 (4
3)
Cana
da20
13Ca
nadi
an T
obac
co,
Alco
hol a
nd
Dru
gs S
urve
y (C
TAD
S)e
2 10
5Th
e sa
mpl
e de
sign
is
a tw
o-ph
ase stratifi
ed
rand
om s
ampl
e of
te
leph
one
num
bers
. In
the
first pha
se, hou
seho
lds
are
sele
cted
usi
ng
rand
om d
igit
dial
ling.
In
the
seco
nd p
hase
, one
or
two
indi
vidu
als
(or n
one)
ar
e se
lect
ed b
ased
upo
n ho
useh
old
com
posi
tion
F: 49%
M: 5
1%
15–
19
year
sQ
uest
ionn
aire
, te
leph
one
30 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Surís
, 201
5 (4
9)
Switz
erla
nd20
14D
ata
wer
e dr
awn
from
ado
@in
tern
et.c
h, a
lo
ngitu
dina
l st
udy
on In
tern
et
use
base
d on
a
repr
esen
tativ
e sa
mpl
e of
st
uden
ts in
th
e Fr
ench
-sp
eaki
ng p
art o
f Sw
itzer
land
621
A ra
ndom
sam
ple
of 3
5 sc
hool
s w
ere
invi
ted
to p
artic
ipat
e in
the
ado@
inte
rnet
.ch
stud
y in
201
2. A
sub
sam
ple
from
the
ado@
inte
rnet
.ch
stu
dy c
onse
nted
to
bein
g co
ntac
ted
and
wer
e fo
llow
ed u
p in
this
wav
e
F: 50.4%
M: 49.6%
16.2
yea
rsW
eb-b
ased
qu
estio
nnai
re
Wan
g, 2
015
(17)
Ch
ina
(Hon
g Ko
ng S
pe-
cial
Adm
in-
istr
ativ
e Re
gion
)
2012
–20
13Q
uest
ionn
aire
ad
apte
d fr
om
the
Glob
al Y
outh
To
bacc
o Su
rvey
(G
YTS)
45 128
Scho
ol s
ampl
ing
was
stratifi
ed by distric
t, m
ixed
/sin
gle
sex
education, fina
ncial
supp
ort,
and
scho
ol ty
pe
F: 48.6%
M: 51.4%
12–18
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
West, 20
12; F
idler,
2011
(53,
51)
U
nite
d Ki
ngdo
m
(Eng
land
)
2014
, 201
5Sm
okin
g To
olki
t St
udy
1 40
5 (201
4),f
1 33
2 (2
015)
Base
line
surv
eys
wer
e co
nduc
ted
via
mon
thly
cro
ss-s
ectio
nal
hous
ehol
d co
mpu
ter-
assi
sted
inte
rvie
ws
of
approx
imately 1 80
0 ad
ults
age
d 16
and
ove
r in
Eng
land
, usi
ng ra
ndom
lo
catio
n qu
ota
sam
plin
g,
and stratifi
catio
n by A Classificatio
n O
f Res
iden
tial
Nei
ghbo
urho
ods
(ACO
RN)
char
acte
ristic
s
Not
pr
ovid
ed16
–20
ye
arsf
Face
to fa
ce
31 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Firs
t aut
hor’s
last
na
me,
yea
rCo
untr
y of
dat
a co
llect
ion
Year
of
data
co
llect
ion
Surv
ey n
ame
nSa
mpl
ing
fram
eSe
x (%
)Ag
e ra
nge
Dat
a co
llect
ion
mod
ality
Whi
te, 2
015
(39)
N
ew
Zeal
and
2012
, 201
4Yo
uth
Insi
ghts
Su
rvey
3 12
7 (2
012)
, 2 91
9 (201
4)
A tw
o-st
age
clus
ter
sam
ple
desi
gn to
obt
ain
a na
tiona
lly re
pres
enta
tive
sam
ple
of N
ew Z
eala
nd
year
10
stud
ents
was
use
d
(201
2)
F: 49%
M: 5
1%
(201
4)
F: 49.8%
M: 5
0.2%
14–15
ye
ars
Que
stio
nnai
re,
pen
and
pape
r
a. D
ata
obta
ined
from
web
site
. Cen
tres
for D
isea
se C
ontr
ol a
nd P
reve
ntio
n. S
mok
ing
and
toba
cco
use:
Nat
iona
l You
th T
obac
co S
urve
y (N
YTS)
. [In
tern
et].
Cent
res
for
Disease Con
trol and
Prevention; 201
5 [upd
ated
201
5 Se
p 9; cite
d 20
15 Oct 2]. Av
ailable from
: htt
p://
ww
w.c
dc.g
ov/t
obac
co/d
ata_
stat
istic
s/su
rvey
s/ny
ts/.
b. A
geo
demog
raph
ic classificatio
n system
that describes dem
ograph
ic and
lifestyle profi
les of small g
eograp
hical a
reas.
c. Results of sub
grou
p an
alyses provide
d by autho
rs. O
riginal pub
lication: Gallus S, Lug
o A, Pacifici R, Pichini S, Colom
bo P, Garattin
i S et a
l. E-ciga
rette aw
aren
ess,
use, and
harm perceptions in
Italy: a nationa
l rep
resentative survey. N
icotine an
d Toba
cco Re
search. 201
4;16
(12):154
1–8.
d. D
ata
obta
ined
from
web
site
. Flo
rida
Hea
lth.
201
1 Fl
orid
a Yo
uth
Toba
cco
Surv
ey re
port
s: F
act S
heet
3: Y
outh
sm
okel
ess
toba
cco
use.
[Int
erne
t]. F
lorid
a D
epar
tmen
t
of Health; 201
5 [upd
ated
201
5 Se
p 9; cite
d 20
15 Oct 2]. Av
ailable from
: http://www.floridah
ealth.go
v/statistic
s-an
d-da
ta/survey-da
ta/fl-you
th-tob
acco-survey/_
docu
men
ts/2
011-
stat
e/in
dex1
.htm
l.
e. D
ata
obta
ined
from
web
site
. Gov
ernm
ent o
f Can
ada.
Sum
mar
y of
resu
lts
for 2
013:
Can
adia
n To
bacc
o, A
lcoh
ol a
nd D
rugs
Sur
vey
(CTA
DS)
. [In
tern
et].
Gove
rnm
ent
of Can
ada; 201
5 [upd
ated
201
5 Fe
b 3; cite
d 20
15 Oct 2]. Av
ailable from
: hea
lthy
cana
dian
s.gc
.ca/
scie
nce-
rese
arch
-sci
ence
s-re
cher
ches
/dat
a-do
nnee
s/ct
ads-
ecta
d/
sum
mar
y-so
mm
aire
-201
3-en
g.ph
p.
f. U
pdat
ed re
sult
s fo
r thi
s su
bgro
up (u
npub
lishe
d da
ta) w
ere
prov
ided
by
corr
espo
ndin
g au
thor
. Orig
inal
pub
licat
ion:
Fid
ler J
A, S
haha
b L,
Wes
t O, J
arvi
s M
J, M
cEw
en A
,
Stap
leton JA et a
l. “Th
e sm
oking toolkit study”: a na
tiona
l study of smoking an
d sm
oking cessation in Eng
land
. BMC Pu
blic Health. 201
1;11
(1):1
–9.
32 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Tabl
e 2.
Stu
dy c
hara
cter
istic
s of
all
incl
uded
stu
dies
for o
bjec
tive
2
Firs
t aut
hor’s
la
st n
ame,
ye
ar, c
ount
ry
of d
ata
colle
ctio
n
Stud
y de
sign
nSa
mpl
ing
fram
eSe
x (%
)Ag
e,
mea
nO
utco
mes
Dat
a co
llect
ion
mod
ality
Follo
w-
up ti
me
poin
ts
Cova
riate
s ad
just
edRe
sults
Leve
ntha
l, 20
15, U
nite
d St
ates
(54)
Long
itudi
nal,
pros
pect
ive
coho
rt s
tudy
2 50
2St
uden
ts in
pu
blic
hig
h sc
hool
s in
the
Los
Ange
les
met
ropo
litan
ar
ea, c
hose
n be
caus
e of
th
eir d
iver
se
dem
ogra
phic
ch
arac
teris
tics
and
prox
imity
F: 5
3.2%
M:
46.8%
14.06
year
s (9
5% C
I: 14
.04–
14.07)
Use
of
ciga
rett
es
and
othe
r co
m-
bust
ible
ni
cotin
e pr
oduc
ts
in th
e pa
st
six
mon
ths
Surv
eys
eith
er in
pe
rson
, te
leph
one
or In
tern
et
Six
and
12
mon
ths
Soci
odem
ogra
phic
(a
ge, s
ex, r
ace,
hi
gher
par
enta
l ed
ucat
ion)
, en
viro
nmen
tal
fact
ors
(livi
ng
situ
atio
n, p
eer
smok
ing)
and
in
trap
erso
nal
fact
ors
(men
tal h
ealt
h,
pers
onal
ity tr
aits
, ps
ycho
logi
cal
proc
ess)
ass
ocia
ted
with
sm
okin
g, ri
sky
beha
viou
r and
sm
okin
g
SEIS
eve
r use
rs
at b
asel
ine
had
sign
ificantly
incr
ease
d od
ds
of u
sing
any
co
mbu
stib
le
toba
cco
prod
ucts
(AOR 2.73
; 95%
CI: 2.00–
3.73
; P ≤ 0.00
1) and
ci
gare
ttes
(AO
R 1.75
; 95%
CI: 1.10
–2.77
; P = 0.02).
Prim
ack,
20
15, U
nite
d St
ates
(55)
Long
itudi
nal,
pros
pect
ive
coho
rt s
tudy
694
Dat
a co
llect
ed
from
in
divi
dual
s th
at h
ad b
een
part
of a
larg
e na
tiona
lly
repr
esen
tativ
e U
nite
d St
ates
st
udy
F: 5
3.9%
M:
46.1%
19.5
ye
ars
(SD
2.0
) fo
r SEI
S users;
20 y
ears
(SD 2.4)
for n
on-
user
s
Initi
atio
n of
sm
ok-
ing
Tele
phon
e su
rvey
12
mon
ths
Soci
odem
ogra
phic
, pe
rson
al a
nd
envi
ronm
enta
l va
riabl
es
incl
udin
g ag
e, s
ex,
race
, mat
erna
l ed
ucat
ion,
se
nsat
ion-
seek
ing
tend
ency
, par
enta
l sm
okin
g an
d pe
er
smok
ing
Indi
vidu
als
who
wer
e no
n-su
scep
tible
no
n-sm
oker
s an
d SE
IS e
ver u
sers
at
bas
elin
e ha
d sign
ificantly highe
r od
ds o
f usi
ng
ciga
rett
es a
t 12
mon
ths
follo
w-u
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33 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
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34 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.2 Risk of bias 4.2.1 Objective 1Eight of 32 studies satisfied seven of 10 quality assessment criteria, 17 satisfied five or six criteria, and seven satisfied three or four criteria (Figure A4.3). For 22 of the 32 included studies, the study sample was deemed to be representative of the target population. For the majority of these studies, staged cluster sampling and statistical weights were used to ensure the sample was representative of the target population. For the remainder of the studies, sample representativeness was unclear as data weighting was not reported, nor was comparison made between the characteristics of the sample and the target population. Nineteen of the 32 studies described the study setting and the demographics of study subjects in enough detail for comparison to be made to other populations. For all studies apart from four, participant recruitment was rated as appropriate due to random sampling of clusters and participants. In addition, 25 of the 32 studies were deemed to have an adequate sample size. Twenty-two of the 32 studies undertook data weighting to correct for bias due to non-response and ensure sufficient coverage of the sample. For all studies excepted one, the objectivity of the measures was not reported. The reliability of the measures was not reported for all studies. All studies conducted appropriate statistical analysis based on the study aims. The majority (20 of 32) identified and accounted for important confounders and subgroups through regression analysis.
4.2.2 Objective 2As shown in Figure A4.4, none of the longitudinal studies were classified as having a sample representative of the target population. All three studies described the study setting and the demographics of study subjects in detail. The precision of the prevalence estimates in Primack et al. (55) was limited by the small number of participants who reported SEIS use at baseline (n=16). For all studies it was unclear whether the self-reported methods for collecting data on SEIS use and subgroup characteristics were reliable. Also, while Leventhal et al. (54) reported that all measures used in the study had adequate psychometric properties, the validity of the measures used in Primack et al. (55) and Wills (56) was unclear. All studies conducted appropriate statistical analysis, accounting for important confounders associated with cigarette use, such as sex, age, ethnicity and smoking status of family and friends. Appropriately, all studies also used a multiple imputation approach to address attrition bias and examined association only in young people where tobacco smoking was absent at baseline.
4.3 Overall prevalence of SEIS use among young people (objective 1) Prevalence of SEIS ever use between 2013 and 2015. The pooled estimate of the prevalence of SEIS ever use from 20 studies conducted between 2013 and 2015 was 16.4% (95% CI: 12.5–20.6%) (Figure A4.5). Among the 14 studies that reported data by sex, the prevalence was 17.4% (95% CI: 10.9–25%) among males and 14.3% (95% CI: 8.7–21%) in females (data not shown). In the sensitivity analyses (Figure A4.6), including
35 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
an additional three studies (49, 50, 52) that did not employ probability sampling (23 studies overall), the prevalence of SEIS ever use was 16.1% (95% CI: 12.6–20.0%) overall, 19.3% (95% CI: 12.5–27.1%) among males (13 studies) and 15.5% (95% CI: 9.9–22.2%) in females (13 studies).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use between 2008 and 2015 by country is shown in Figure A4.7. For four of the five countries where more than one comparable estimate of prevalence was provided over time, prevalence of ever use increased (see Figure A4.7). In the Republic of Korea, prevalence of ever use among 13–19-year-olds increased from 0.5% (95% CI: 0.3–0.8%) in 2008 to 9.4% (95% CI: 9.2–9.6 %) in 2011. In New Zealand, prevalence estimates in 14–15-year-olds increased from 7.0% (95% CI: 6.1–8.0%) to 20.0% (95% CI: 18.6–21.5%) between 2012 and 2014. In Poland, among 15–24-year-olds, prevalence estimates of ever use were 20.9% (95% CI: 20.2–21.6%) in 2010–2011 and 62.1% (95% CI: 59.9–64.2%) in 2013–2014 among 15–19-year-olds. Similarly, in the United States, in nationally representative samples, prevalence of ever use increased from 1.4% (95% CI: 1.2–1.7%) to 3.0% (95% CI: 2.6–3.4%) among middle school children and from 4.7% (95% CI: 4.3–5.1%) to 11.9% (95% CI: 11.3–12.5%) among high school students between 2011 and 2013. Multiple estimates of prevalence over time were also available for Italy, where no difference was observed at the multiple time points (9.2% (95% CI: 5.2–14.7%) in 2013 and 4.4% (95% CI: 1.8–8.8%) in 2015). Different measures however were used for the different data collection years (occasional use in 2014–2015 and ever use for 2013) in Italy.
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current SEIS use from 19 studies conducted between 2013 and 2015 was 5.6% (95% CI: 3.4–8.3%) (Figure A4.8). Among the 12 studies that reported data by sex, the prevalence was 6.3% (95% CI: 3.7–9.6%) among males and 4.3% (95% CI: 2.4–6.8%) in females (data not shown). In the sensitivity analyses (Figure A4.9) with an additional five studies (49–52) (24 studies overall), the prevalence of SEIS ever use was 5.5% (95% CI: 3.5–7.9%) overall, 7.4 % (95% CI: 4.5–10.8%) among males (13 studies) and 4.9% (95% CI: 2.8–7.4%) in females (13 studies).
Change in prevalence of current use between 2008 and 2015. The pooled prevalence of current SEIS use between 2008 and 2015 by country is shown in Figure A4.10. In three of the four countries where multiple comparable estimates of prevalence were available over time, prevalence of current use increased. In Poland, data collected on 15–24-year-olds in 2010–2011 reported 8.2% (95% CI: 7.8–8.7%) current use, compared with 29.9% (95% CI: 27.9–32.0%) among adolescents aged 15–19 years in 2013–2014. In the United States, data from the National Youth Tobacco Survey reported that prevalence of current use increased from 0.6% (95% CI: 0.4–0.8%) in 2011 to 3.9% (95% CI: 3.5–4.3%) among middle school students and from 1.5% (95% CI: 1.3–1.8%) to 13.4% (95% CI: 12.8–14.0%) among high school students between 2011 and 2014. In Hungary, however, the prevalence of current use decreased from 13% (95% CI:
36 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
11.6–14.4%) in 2012 to 9.0% (95% CI: 8.1–9.9%) in 2013 among mainly young people aged 13–15 years. No changes were observed in Italy from 1.8% (95% CI: 0.4–5.3%) in 2013 to 1.3% (95% CI: 0.2–4.4%) in 2015 among adolescents aged 16–19 years.
4.4 Prevalence among non-smokers (objective 1) Prevalence of SEIS ever use between 2013 and 2015. The pooled estimate of the prevalence of SEIS ever use among non-smokers from 13 studies conducted between 2013 and 2015 was 7.0% (95% CI: 5.1–9.3%) (Figure A4.11). In the sensitivity analyses with an additional three studies (40, 50), the prevalence of SEIS ever use from 15 studies overall was 6.4% (95% CI: 4.6–8.5%) (Figure A4.12).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use among non-smokers between 2008 and 2015 by country is shown in Figure A4.13. National survey data of middle and high school students in the United States reported an increase in prevalence of SEIS ever use from 1.8% (95% CI: 1.6–2.0 %) in 2011 and 4.4% (95% CI: 4.1–4.6%) in 2012. There was no change in prevalence of ever use for Italy, where surveys of 16–19-year-olds reported prevalence of ever use of SEIS by non-smokers of 5.1% (95% CI: 2.1–10.3%) in 2013, 0.7% (95% CI: 0.0–3.9%) in 2014, and 1.4% (95% CI: 0.2–5.0%) in 2015.
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current use among non-smokers from 11 studies conducted between 2013 and 2015 was 1.5% (95% CI: 0.3–3.5%) (Figure A4.14). In the sensitivity analyses with an additional four studies (40, 50) (15 studies overall), the prevalence of SEIS ever use was 1.3% (95% CI: 0.4–2.8%) (Figure A4.15).
Change in prevalence of current use between 2008 and 2015. The pooled prevalence of current SEIS use among non-smokers between 2008 and 2015 by country is shown in Figure A4.16. Multiple comparable estimates were available from three countries: Italy, Poland and the United States. In the United States, estimates from the state of Florida found prevalence of current use in non-smokers increased from 0.7% (95% CI: 0.5–1.0%) to 2.8% (95% CI: 2.6–3.0%) among middle school students, and from 0.8% (95% CI: 0.6–1.1%) to 6.9% (95% CI: 6.6–7.2%) among high school students between 2011 and 2014. In United States national samples, the prevalence of current SEIS use was 0.6% (95% CI: 0.5–0.7%) for 11–18-year-olds in 2011, and 1.1% (95% CI: 0.9–1.2) in 2012. In Poland, prevalence was 2.4% (95% CI: 2.1–2.7%) in 2010–2011 and 13.0% (95% CI: 11.2–15.0%) in 2013–2014. No changes were observed in Italy (0% (95% CI: 0.0–2.7%) in 2013, 0% (95% CI: 0.0–2.6%) in 2014, and 0% (95% CI: 0.0–2.6%) in 2015.
37 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
4.5 Prevalence among current smokers (objective 1) Prevalence of SEIS ever use between 2013 and 2015. From the 13 studies conducted from 2013, the pooled estimate of SEIS ever use among current tobacco smokers was 54.7% (95% CI: 47.0–62.3%) (Figure A4.17). In the sensitivity analyses with an additional two studies (50) (15 studies overall), the prevalence of SEIS ever use was 53.2% (95% CI: 45.9–60.5%) (Figure A4.18).
Change in prevalence of ever use between 2008 and 2015. The pooled prevalence of SEIS ever use among current-smokers between 2008 and 2015 by country is shown in Figure A4.19. In Italy and the United States, multiple estimates of prevalence of SEIS ever use were provided over time. In the United States, among nationally representative samples of 11–18-year-old students, the prevalence increased from 28.1% (95% CI: 25.0–31.5%) in 2011 to 58.1% (95% CI: 54.8–61.4%) in 2012. In Italy no changes in estimates were observed in 2013 (29.6%; 95% CI: 13.8–50.2%), in 2014 (35.7%; 95% CI: 12.8–64.9%), and in 2015 (26.3%; 95% CI: 9.1–51.2%).
Prevalence of SEIS current use between 2013 and 2015. The pooled estimate of the prevalence of current SEIS use among current tobacco smokers from the 10 studies conducted from 2013 was 19.4% (95% CI: 8.3–33.5%) (Figure A4.20). In the sensitivity analyses with an additional two studies (50) (14 studies overall), the prevalence of SEIS ever use was 17.8% (95% CI: 8.8–28.9%) (Figure A4.21).
Change in the prevalence of current SEIS use between 2008 and 2015. The pooled prevalence of current SEIS use among current smokers between 2008 and 2015 by country is shown in Figure A4.22. For Poland and the United States, multiple comparable estimates of prevalence available across time showed an increase in current use of SEIS among smokers. In Poland, current use in adolescents increased from 15.3% (95% CI: 14.3–16.4%) in 2010–2011 to 57.4% (95% CI: 53.8–61.0%) in 2013–2014. In the United States, among nationally representative samples of 11–18-year-olds, the prevalence increased from 9.8% (95% CI: 7.8–12.1%) in 2011 to 26.5% (95% CI: 23.6–29.5%) in 2012. No changes in prevalence were observed in Italy between 2013 (11.1%; 95% CI: 2.4–29.2%), 2014 (7.1%; 95% CI: 0.2–33.9%) and 2015 (5.3%; 95% CI: 0.1–26.0%).
4.6 Exploring heterogeneity (for objective 1)To explore reasons for the high observed heterogeneity (> 90%) in the pooled estimates of prevalence (between 2008 and 2015), a meta-regression including year of study, age range, regulation, sex and MPOWER score was undertaken for SEIS ever and current use. For prevalence of ever use, the multivariable model including all five covariates accounted for 44% of the observed heterogeneity, where age range (P < 0.05), regulation (P < 0.05) and year of data collection (P < 0.001) were significant. For current SEIS use, year of data collection (P < 0.05) and MPOWER score (P < 0.05) were significant, with the multivariable model including all five covariates accounting for 24% of the identified heterogeneity.
38 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Among non-smokers and current smokers, sex was not included in meta-regression modelling due to lack of available data. For ever use among non-smokers, none of the variables were significantly associated with prevalence heterogeneity. For current SEIS use among non-smokers, year (P < 0.05), age (P < 0.05) and MPOWER score (P < 0.05) were significantly associated with prevalence heterogeneity and accounted for 40% of the identified heterogeneity.
Among current smokers, year (P < 0.05) and regulation (P < 0.05) were significantly associated with the heterogeneity observed in prevalence ever use, and the multivariable model including regulation, year and age accounted for the largest amount (52%) of heterogeneity. For current SEIS use among smokers, only MPOWER score was significant (P < 0.01), and the multivariable model including all four covariates (year, age, regulation and MPOWER score) explained 24% of the observed heterogeneity.
4.7 Objective 2Three studies (54–56) conducted in the United States were included (see Table 2 for study characteristics). Leventhal and colleagues undertook a prospective longitudinal cohort study with 2530 14-year-old English-speaking adolescents, recruited from 10 demographically diverse schools in Los Angeles, who had never used any combustible tobacco products (54). In a repeated measure using generalized mixed model analysis, including only non-tobacco users and adjusting for school, time (six and 12 months) and other potential demographic, environmental and personal covariates, those students who had ever used SEIS at baseline were significantly more likely to report using at least one puff of combustible tobacco products (described as use of a few puffs in the past six months) at 12 months follow-up (OR 2.73; 95% CI: 2.00–3.73; P ≤ 0.001). This association was significant across the examined tobacco products: cigarettes (OR 1.75; 95% CI: 1.10–2.77, P = 0.02), cigars (OR 2.96; 95% CI: 2.00–4.38; P ≤ 0.001) and hookah (OR 2.26; 95% CI: 1.56–3.29; P ≤ 0.001).
Primack and colleagues (55) examined, in a national sample of individuals aged 16–26 years (mean age 19.5 years for SEIS users and 20 years for non-SEIS users), whether being a non-susceptible non-smoker (defined as those reporting that they definitely would not accept a cigarette from a friend and definitely would not smoke in the next year) who used SEIS at baseline (2012/2013) predicted higher experimentation of tobacco cigarette smoking at 12 months follow-up (2013/2014) (55). In the primary analyses imputing for missing data (n=694), a multivariable multinomial logistic regression adjusting for sex, age, race, education level and sensation-seeking tendency found that individuals who smoked SEIS at baseline had significantly higher odds (AOR 8.3; 95% CI: 1.2–58.6%) of progressing from non-susceptible non-smoker to tobacco cigarette smoking one year post baseline. This finding was consistent across multiple sensitivity analyses undertaken by the authors.
Wills and colleagues (56) undertook a school-based survey with 9th and 10th grade students in Hawaii, United States, to examine whether, among never smokers, those
39 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
who had used e-cigarettes were more likely to have smoked cigarettes at 12-month follow-up. In the adjusted analysis imputing for missing data, individuals who were e-cigarette users at the first time point had an increased odds (AOR 1.67; 95% CI: 1.17–2.39) of smoking at follow-up.
Pooled analysis of the three studies indicated that SEIS smokers at baseline had an increased adjusted odds ratio (AOR 2.19; 95% CI: 1.46–3.3%; I2 = 59.7%) of being a tobacco cigarette user at follow-up (Figure A4.23).
40 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
5. Discussion and conclusion
5.1 DiscussionThis review aimed to describe the prevalence and trends of SEIS use by young people aged between 10 and 20 years; and to examine the association between SEIS use and initiation of tobacco smoking in this group. To describe prevalence and trends, 28 eligible studies of SEIS use among youths that utilized probability sampling were identified. Three longitudinal studies were identified that examined associations between SEIS use and initiation of tobacco smoking.
The prevalence of SEIS use varied considerably within and between countries. Most recent estimates (2013 and 2015) show ever use of SEIS among non-smokers of 7% and prevalence of current use of less than 3%. Among smokers, in countries including Canada, Ireland, New Zealand, the United Kingdom and the United States, more than 50% of smokers had ever used SEIS, while in Poland, the Republic of Korea and the United States, over 20% were current users. Use of SEIS among smokers and non-smokers was reportedly increasing in Poland and in the United States but not for countries such as Italy, where current SEIS use remained relatively stable. In the sensitivity analyses, small increases in prevalence of SEIS current use among smokers and non-smokers were observed.
Observed differences between countries in prevalence and trends could potentially be attributed to differences in regulation governing the promotion of SEIS and their sale to young people. For example, the authors of the Polish studies suggested that the greater increase in SEIS use among Polish adolescents may be due to availability of SEIS in the market, more aggressive marketing of SEIS, and lower levels of regulation (11). The increase in SEIS use has also coincided with reduced prevalence of current tobacco use globally (12, 57). This has led to suggestions that smokers who have quit smoking may potentially be substituting tobacco smoking with SEIS. This review however found that a large proportion of young smokers were current SEIS users, suggesting that smokers may continue to use SEIS concurrently with traditional cigarettes. Findings from the meta-regression suggest that a number of factors, including MPOWER scores, time (year) and participant age, may be associated with prevalence heterogeneity of current/
41 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
ever e-cigarette use. These findings however need to be interpreted with caution, as there is likely to be other unmeasured confounders that have not been considered in this analysis. Further longitudinal research assessing the potential impact of MPOWER scores or policy regulation on SEIS use is probably needed to ascertain the impact of such strategies on prevalence of use in youths.
Pooled data from three longitudinal studies (54, 55) found that the use of SEIS by non-smokers more than doubled the odds of experimentation with tobacco smoking within 12 months. Although a number of design limitations exist, these findings support evidence from previous cross-sectional studies and provide early evidence of a positive association between SEIS use and intentions to try tobacco smoking (17–19). The specific pathway by which SEIS use could lead to uptake of tobacco products is unknown. However, the enjoyment of the sensory tobacco-related cues associated with SEIS use (e.g. inhalation, exhalation) (58), the pharmacological effects of consuming nicotine, and the biological and environmental vulnerability during youth and adolescence have been hypothesized to contribute to an increased inclination of SEIS users to try other nicotine-providing tobacco products (59). Further, other researchers suggest that SEIS may act as catalyst, both in supporting initial initiation of SEIS use and facilitating transition to cigarette uptake (16).
These findings need to be interpreted in light of the limitations of this review. First, all included studies utilized self-reported measures of SEIS use. To our knowledge, the validity of such assessment methods has not been established. Measures such as ever use and use in last 30 days may not provide an appropriate indication of established use behaviours (60). Second, for assessment of current use, this review pooled a variety of measures, primarily “regular use” and “use in the last 30 days”, which may have influenced prevalence estimates for some countries. Third, this study also examined tobacco use among non-smokers rather than never smokers. While it is likely that individuals with previous nicotine dependence may have been included, estimates of tobacco use among youths indicates that the majority of non-smoking youths (> 80%) have never smoked (27, 61). Further, there was considerable variability in the definition of smokers in the included studies, which may have resulted in experimenters being classed as current smokers. Fourth, considerable and statistically significant heterogeneity was found among all pooled estimates presented in the review. For prevalence heterogeneity, the I2 exceeded 70% for each case. None of the covariates examined in the meta-regression significantly accounted for the statistical heterogeneity observed in the meta-analyses of current SEIS use, suggesting that other personal or environmental factors may need to be considered. Finally, only three longitudinal studies were identified to examine associations between SEIS use by non-smokers and later initiation of tobacco. Further research is required to substantiate the findings of such studies.
42 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
5.2 ConclusionDespite SEIS use among non-smoking young people remaining relatively low in most jurisdictions, the finding of a small but significant longitudinal association between SEIS use and tobacco use and of increasing prevalence of SEIS use among non-smoking young people in some countries supports the need for strategies to discourage SEIS use among non-smokers.
43 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
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22. Durmowicz EL. The impact of electronic cigarettes on the paediatric population. Tobacco Control. 2014;23(Suppl. 2):ii41–6.
23. Munn Z, Moola S, Riitano D, Lisy K. The development of a critical appraisal tool for use in systematic reviews addressing questions of prevalence. International Journal of Health Policy and Management. 2014;3(3):123–8.
24. Babineau K, Taylor K, Clancy L. Electronic cigarette use among Irish youth: a cross-sectional study of prevalence and associated factors. PLoS ONE. 2015;10(5):e0126419.
25. Gallus S, Lugo A, Pacifici R, Pichini S, Colombo P, Garattini S et al. E-cigarette awareness, use, and harm perceptions in Italy: a national representative survey. Nicotine and Tobacco Research. 2014;16(12):1541–8.
26. Li J, Newcombe R, Walton D. The prevalence, correlates and reasons for using electronic cigarettes among New Zealand adults. Addictive Behaviors. 2015;45:245–51.
27. Moore G, Hewitt G, Evans J, Littlecott HJ, Holliday J, Ahmed N et al. Electronic-cigarette use among young people in Wales: evidence from two cross-sectional surveys. BMJ Open. 2015;5(4):e007072. doi:10.1136/bmjopen-2014-007072.
28. Anand V, McGinty KL, O’Brien K, Guenthner G, Hahn E, Martin CA. E-cigarette use and beliefs among urban public high school students in North Carolina. Journal of Adolescent Health. 2015;57(1):46–51.
29. Arrazola RA, Neff LJ, Kennedy SM, Holder-Hayes E, Jones CD. Tobacco use among middle and high school students: United States, 2013. Morbidity and Mortality Weekly Report. 2014;63(45):1021–6.
30. Barnett TE, Soule EK, Forrest JR, Porter L, Tomar SL. Adolescent electronic cigarette use: associations with conventional cigarette and hookah smoking. American Journal of Preventive Medicine. 2015;49(2):199–206.
31. Corey C, Baoguang W, Johnson SE, Apelberg B, Husten C, King BA et al. Electronic cigarette use among middle and high school students. Oncology Times. 2013;35(19):36. [Reprinted (slightly edited) from Morbidity and Mortality Weekly Report. 2013;62:729–30.]
32. Johnston LD, O’Malley PM, Miech RA, Bachman JG, Schulenberg JE. Monitoring the future national survey results on drug use 1975–2014: overview, key findings on adolescent drug use. Ann Arbor: Institute for Social Research, University of Michigan; 2015.
33. Porter L, Duke J, Hennon M, Dekevich D, Crankshaw E, Homsi G et al. Electronic cigarette and traditional cigarette use among middle and high school students in Florida, 2011–2014. PLoS ONE. 2015;10(5):e0124385.
46 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
34. Pepper JK, Reiter PL, McRee AL, Cameron LD, Gilkey MB, Brewer NT. Adolescent males’ awareness of and willingness to try electronic cigarettes. Journal of Adolescent Health. 2013;52(2):144–50.
35. 2015 Alaska Youth Risk Behavior Survey results 2015. Alaska Department of Health and Social Services (http://dhss.alaska.gov/dph/Chronic/Pages/yrbs/yrbsresults.aspx).
36. 2015 Montana Youth Risk Behaviour Survey high school results 2015. Montana Office of Public Instruction (http://opi.mt.gov/pdf/YRBS/15/15MT_YRBS_FullReport.pdf).
37. Cho JH, Shin E, Moon SS. Electronic-cigarette smoking experience among adolescents. Journal of Adolescent Health. 2011;49(5):542–6.
38. Lee S, Grana RA, Glantz SA. Electronic cigarette use among Korean adolescents: a cross-sectional study of market penetration, dual use, and relationship to quit attempts and former smoking. Journal of Adolescent Health. 2014;54(6):684–90.
39. White J, Li J, Newcombe R, Walton D. Tripling use of electronic cigarettes among New Zealand adolescents between 2012 and 2014. Journal of Adolescent Health. 2015;56(5): 522–8.
40. Scottish Schools Adolescent Lifestyle and Substance Use Survey (SALSUS): smoking among 13 and 15 year olds in Scotland 2013. Edinburgh, United Kingdom: NHS National Services Scotland; 2014.
41. Goniewicz ML, Zielinska-Danch W. Electronic cigarette use among teenagers and young adults in Poland. Pediatrics. 2012;130(4):e879–85.
42. Hungarian and foreign data and statistics: Global Youth Tobacco Survey. Hungarian Focal Point for Tobacco Control (http://www.fokuszpont.dohanyzasvisszaszoritasa.hu/en/content/hungarian-and-foreign-data-statistics).
43. Reid JL, Hammond D, Rynard VL, Burkhalter R. Tobacco use in Canada: patterns and trends, 2015 edition. Waterloo, ON: Propel Centre for Population Health Impact, University of Waterloo; 2015.
44. Hamilton HA, Ferrence R, Boak A, Schwartz R, Mann RE, O’Connor S et al. Ever use of nicotine and non-nicotine electronic cigarettes among high school students in Ontario, Canada. Nicotine and Tobacco Research. 2015;17(10):1212–8. doi:10.1093/ntr/ntu234.
45. Dautzenberg B, Birkui P, Noel M, Corsett J, Osman M, Dautzenberg M. E-cigarette: a new tobacco product for schoolchildren in Paris. Open Journal of Respiratory Diseases. 2013;3(1):21–4.
47 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
46. Kristjansson AL, Mann MJ, Sigfusdottir ID. Licit and illicit substance use by adolescent e-cigarette users compared with conventional cigarette smokers, dual users, and nonusers. Journal of Adolescent Health. 2015;57(5):562–4.
47. Fotiou A, Kanavou E, Stavrou M, Richardson C, Kokkevi A. Prevalence and correlates of electronic cigarette use among adolescents in Greece: a preliminary cross-sectional analysis of nationwide survey data. Addictive Behaviors. 2015;51:88–92.
48. Pepper JK, Emery SL, Ribisl KM, Brewer NT. How U.S. adults find out about electronic cigarettes: implications for public health messages. Nicotine and Tobacco Research. 2014;16(8):1140–4.
49. Surís J-C, Berchtold A, Akre C. Reasons to use e-cigarettes and associations with other substances among adolescents in Switzerland. Drug and Alcohol Dependence. 2015;153:140–4.
50. Eastwood B, Dockrell MJ, Arnott D, Britton J, Cheeseman H, Jarvis MJ et al. Electronic cigarette use in young people in Great Britain 2013–2014. Public Health. 2015;129:1150–6.
51. Fidler JA, Shahab L, West O, Jarvis MJ, McEwen A, Stapleton JA et al. “The smoking toolkit study”: a national study of smoking and smoking cessation in England. BMC Public Health. 2011;11(1):1–9.
52. Ford A, MacKintosh AM, Bauld L, Moodie C, Hastings G. Adolescents’ responses to the promotion and flavouring of e-cigarettes. International Journal of Public Health. 2016;61(2):215–24.
53. West R, Owen L. Estimates of 52-week continuous abstinence rates following selected smoking cessation interventions in England, 2012 (http://www.smokinginengland.info/reports/).
54. Leventhal AM, Strong DR, Kirkpatrick MG et al. Association of electronic cigarette use with initiation of combustible tobacco product smoking in early adolescence. Journal of the American Medical Association. 2015;314(7):700–7.
55. Primack BA, Soneji S, Stoolmiller M, Fine MJ, Sargent J. Initiation of cigarette smoking after electronic cigarette use: a national study of young adults. Journal of General Internal Medicine. 2015;30:S193.
56. Wills TA, Knight R, Sargent JD, Gibbons FX, Pagano I, Williams RJ. Longitudinal study of e-cigarette use and onset of cigarette smoking among high school students in Hawaii. Tobacco Control. 2016. doi:10.1136/tobaccocontrol-2015-052705. [Epub ahead of print].
57. WHO global report on trends in prevalence of tobacco smoking, 2015. Geneva: World Health Organization; 2015.
48 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
58. Rees VW, Kreslake JM, Wayne GF, O Connor RJ, Cummings KM, Connolly GN. Role of cigarette sensory cues in modifying puffing topography. Drug and Alcohol Dependence. 2012;124(1–2):1–10.
59. Kristjansson AL, Sigfusdottir ID. E-cigarette use and relations to tobacco and alcohol use among adolescents. BMC Medicine. 2015;13:103.
60. Amato MS, Boyle RG, Levy D. How to define e-cigarette prevalence? Finding clues in the use frequency distribution. Tobacco Control. 2016;25(e1):e24–9. doi:10.1136/tobaccocontrol-2015-052236.
61. Dutra LM, Glantz SA. High international electronic cigarette use among never smoker adolescents. Journal of Adolescent Health. 2014;55(5):595–7.
49 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 1: Search terms employed in the electronic databases
CINAHL# Searches
S1 e-cig*
S2 electr* cig*
S3 (MH “Electronic Cigarettes”)
S4 vaping
S5 “electronic nicotine”
S6 e-hookah*
S7 electronic hookah*
S8 e-nicotine
S9 S1 OR S2 OR S3 OR S4 OR S5 OR S6 OR S7 OR S8
COCHRANE LIBRARY# Searches
1 MeSH descriptor: [Electronic Cigarettes] this term only
2 e-cig*.mp
3 electr* cig*.mp
4 vaping.mp
5 electronic nicotine.mp
6 e-hookah*.mp
7 electronic hookah*.mp
8 e-nicotine.mp
9 {or #1-#8}
50 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Database(s): Embase 1974 to 2015 Week 31# Searches
1 w-cig*.mp.
2 electr* cig*.mp.
3 vaping.mp.
4 electronic nicotine.mp.
5 e-hookah*.mp.
6 electronic hookah*.mp.
7 e-nicotine.mp.
8 electronic cigarette/
9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
Database(s): MEDLINE 1946 to Present with Daily Update# Searches
1 e-cig*.mp.
2 electr* cig.mp.
3 Electronic Cigarettes/
4 vaping.mp.
5 electronic nicotine.mp.
6 e-hookah*.mp.
7 electronic hookah*.mp.
8 e-nicotine.mp.
9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
51 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Database(s): MEDLINE In-Process & Other Non-Indexed Citations# Searches
1 e-cig*.mp.
2 electr* cig*.mp.
3 vaping.mp.
4 electronic nicotine.mp.
5 e-hookah*.mp.
6 electronic hookah*.mp.
7 e-nicotine.mp.
8 electronic cigarette/
9 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8
Database(s): PsycINFO 1806 to July Week 3 2015# Searches
1 w-cig*.mp.
2 electr* cig*.mp.
3 vaping.mp.
4 electronic nicotine.mp.
5 e-hookah*.mp.
6 electronic hookah*.mp.
7 e-nicotine.mp.
8 1 or 2 or 3 or 4 or 5 or 6 or 7
52 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 2: Data extraction form (adapted from Cochrane data collection form for intervention reviews)
Citations Author’s name, publication year
Study design Country of study
Year of Data Collection
Type of study
Aims
Survey name/ database
Sample (n) Approached
Eligible
Consent
Analysed
Sampling frame, recruitment method (including sampling unit)
Participants Inclusion criteria
Exclusion criteria
Sex (%)
Age, mean (SD), range
Age range
Race/ethnicity
Socioeconomic status
Other relevant sociodemographic
Subgroups analysed by
Data collection Data collection modality
Measure used
Measures Outcomes (e.g. ever used, current use)
e-cigarette type (if specified)
Total (Final sample) n
Prevalence
Upper 95% CI
Lower 95% CI
53 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Male (Final sample) n
Prevalence
Upper 95% CI
Lower 95% CI
Female (Final sample) n
Prevalence
Upper 95% CI
Lower 95% CI
Other Other results
Analysis and statistical adjustments
Notes
54 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 3: Definition of e-cigarette or SEIS use within included studiesCitation Survey name/
DatabaseEver e-cigarettes user measure
Current e-cigarettes user measure
Alaska Department of Health and Social Services
2015 Alaska Youth Risk Behavior Survey Results
Youth Risk Behaviour Survey
Percentage of students who ever used electronic vapor products (e-cigarettes, e-cigars, e-pipes, vape pipes, vaping pens, e-hookahs, and hookah pens such as blu, NJOY, or Starbuzz)
Percentage of students who currently used electronic vapor products (e-cigarettes, e-cigars, e-pipes, vape pipes, vaping pens, e-hookahs, and hookah pens such as blu, NJOY, or Starbuzz on at least 1 day during the 30 days before the survey)
Anand 2015
E-cigarette use and beliefs among urban public high school students in North Carolina
47-item “High School Questionnaire” 2013 modelled after Monitoring the Future with additional information
Have you ever used an e-cigarette?
• Yes
• No
When was the last time you used an e-cigarette?
• Have never used an e-cigarette
• Today
Arrazola 2014
Tobacco Use Among Middle and High School Students US 2013
2013 National Youth Tobacco Survey (NYTS)
Ever use of electronic cigarettes was determined by asking, “Which of the following tobacco products have you ever tried, even just one time: bidis, kreteks, hookah, snus, dissolvable tobacco, and electronic cigarettes?”
Current use of electronic cigarettes was determined by asking, “During the past 30 days, which of the following products have you used on at least 1 day- bidis, kreteks, hookah, snus, dissolvable tobacco, and electronic cigarettes?”
Arrazola 2015
Tobacco Use Among Middle and High School Students US 2011-2014
2014 National Youth Tobacco Survey (NYTS)
Not reported During the past 30 days, on how many days did you use e-cigarettes such as Blu, 21st Century Smoke, or NJOY?
55 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/Database
Ever e-cigarettes usermeasure
Current e-cigarettesuser measure
Babineau 2015
Electronic cigarette use among Irish youth: a cross sectional study of prevalence and associated factors
2014 Youth Perception of Plain Packaging Study, a nationally representative school-based survey of 16-17 year olds
Respondents who selected one of the following as statement that best describes them:
• I have tried an e-cigarette once or twice but don’t use one regularly
• I used to smoke e-cigarettes but have given up
Respondents who selected one of the following as statement that best describes them:
• I smoke an e-cigarette at least once a month
• I smoke an e-cigarette at least once a week
• I smoke an e-cigarette every
day.
Barnett 2015
Adolescent electronic cigarette use associations with conventional cigarette and hookah smoking
2013 Florida Youth Tobacco Survey
Have you ever tried, even once, electronic cigarette?
• Yes
• No
During the past 30 days, have you used an electronic cigarette?
• Yes
• No
Cho 2011
Electronic Cigarette smoking experience among adolescents
2008 Health Promotion Fund Project in Korea
Have you ever smoked a cigarette, even one or two puffs?
• Yes
• No
Not reported
Corey 2014
Electronic cigarette use among middle and high school students - United States, 2011-2012
Data are from the annual 2011-2012 National Youth Tobacco Survey (NYTS)
see Arrazola 2014 see Arrazola 2014
Dautzenberg 2013
E-cig : a new tobacco product for school children in Paris
2012 annual survey conducted by Paris San Tabac.
Have you ever used an e-cigarette?
• Yes
• No
Not assessed
Dutra 2014
Electronic cigarettes and conventional cigarette use among U.S. adolescents: a cross-sectional study
National Youth Tobacco Survey (NYTS)
see Arrazola 2014 see Arrazola 2014
56 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Eastwood 2015
Electronic cigarette use in young people in Great Britain 2013–2014
YouGov 2013/2014 You said that you have tried an e-cigarette…
Which ONE of the following BEST applies to you?
• I tried smoking a real cigarette before I first tried using an e-cigarette
• I tried using an e-cigarette before I first tried smoking a real cigarette
• I have never smoked a real cigarette but have tried an e-cigarette
• I don’t remember
Those who had heard of e-cigarettes were then asked to describe their experience of e-cigarettes with options range from ‘never use’ to ‘more than once a week’. The following responses were categorised as ‘monthly or more users’:
• I use them sometimes (more than once a month)
• I use them often (more than once a week)
Fidler 2011 The
smoking toolkit study’: a national study of smoking and smoking cessation in England
Smoking Toolkit Study Not assessed Other than yourself, does anyone regularly smoke cigarettes or use an e-cigarette in your presence, such as at your home, work, car or other places that you visit regularly?
• Yes – cigarettes only
• Yes – e-cigarettes only
• Yes – both cigarettes and e-cigarettes
• No – neither cigarettes nor e-cigarettes
57 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Ford 2016
Adolescents’ responses to the promotion and flavouring of e-cigarettes
Youth Tobacco Policy Survey (YTPS)
Ever smokers included those who indicated being regular smokers (at least one cigarette a week), occasional smokers (less than one a week), those who used to smoke and those who had tried smoking only once.
Which of these best describes whether or not you have ever used or tried e-cigarettes?
• I have never used e-cigarettes
• I have only ever tried e-cigarettes once or twice
• I have used e-cigarettes in the past, but I never use them now
• I occasionally use e-cigarettes (less than once a month)
• I use e-cigarettes at least once a month
• I use e-cigarettes at least once a week
Not assessed
Fotiou 2015
Prevalence and correlates of electronic cigarette use among adolescents in Greece: a preliminary cross- sectional analysis of nationwide survey data
2014 Health Behaviour in School-aged Children Survey (HSBC)
Have you ever used an electronic cigarette?
• Never
• Yes
• Only 1-2 times
• Yes more than twice
• Yes more than twice and I use it now
Have you ever used an electronic cigarette?
• Never
• Yes
• Only 1-2 times
• Yes more than twice
• Yes more than twice and I use it now
58 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Gallus 2014
E-Cigarette Awareness, Use, and Harm Perceptions in Italy: A National Representative Survey
Additional analyses from author
Structured questionnaire in the context of a computer assisted personal in-house interview in 2013-2015.
Have you ever heard about e-cigarettes, have you ever tried them or do you have the intention to try them?
• I heard about e-cigarettes and I tried them.
Participants reporting they “have heard about e-cigarettes and have tried them” were labelled as “ever users” of e-cigarettes.
Do you use, occasionally or regularly, the e-cigarette?
• Yes,
occasionally
• Yes, regularly
• I used it in the past
• No
Those who responded yes regularly were classed as current users
Goniewicz 2012
Electronic Cigarette Use Among Teenagers and Young Adults in Poland
The data was collected as part of a national survey on water pipe smoking in 2010-2011, and 2013-2014. Name of survey was unspecified.
Have you ever heard about electronic cigarettes (e-cigarettes)?
• Yes
• No
Have you ever used an e-cigarette?
• Yes
• No
Have you used an e-cigarette at least once in the previous 30 days?
• Yes
• No
Goniewicz 2014
Rise in Electronic Cigarette Use Among Adolescents in Poland
The 2012 and 2011 data was subsample of 2 of the regions included as part of a national survey on water pipe smoking. Name of survey was unspecified. Data
for 2013-2014 were collected from the same 2 regions.
Students were asked whether they had ever smoked or puffed on e-cigarettes (even a single puff).
Students were asked whether they had currently (in the past 30 days) smoked or puffed on e-cigarettes (even a single puff).
59 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Hamilton 2015
Waterpipe use among high school students in Ontario: Demographic and substance use correlates
2013 Ontario Student Drug Use and Health Survey
Have you ever smoked at least one puff from an electronic cigarette?
• Smoking an e-cigarette with nicotine
• Smoking an e-cigarette without
nicotine
• Never smoked but have heard of e-cigarettes
• Never heard of e-cigarettes
Not assessed
Hungarian Focal Point for Tobacco Control. Hungarian and Foreign Data & Statistics: Global Youth Tobacco Survey
Global Youth Tobacco Survey
Not assessed Those who smoked e-cigarette during the past 30 days
Johnston 2014
Key Findings on Adolescent Drug Use
Monitoring the future: National survey 2014 result on drug use
Not reported Prevalence of use in the prior 30 days.
Kristjansson 2015
E-cigarette use and relations to tobacco and alcohol use among adolescents
Youth in Iceland Survey
Not reported Not assessed
Lee 2014
Electronic Cigarette Use Among Korean Adolescents: A Cross-Sectional Study of Market Penetration, Dual Use, and Relationship to Quit Attempts and Former Smoking
2011 Korean Youth Risk Behaviour Web-Survey
Have you ever used an e-cigarette?
• Yes
• No
Have you used e-cigarettes in the past 30 days?
• Yes
• No
60 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Li 2015
The prevalence, correlates and reasons for using electronic cigarettes among New Zealand adults
2014 Health and Lifestyles Survey (HLS)
Have you ever tried an electronic cigarette?
• Yes
• No
Which best describes how often you use an electronic cigarette now?
• At least once a day
• At least once a week
• At least once a month
• Less often than once a month
• Do not use one now
Current use was defined as at least once a month.
Montana Office of Public Instruction 2015 Montana Youth Risk Behaviour Survey High School Results
Montana Youth Behavioural Risk Factor
Electronic vapor products, such as blu, NJOY, or Starbuzz, include e-cigarettes, e-cigars, e-pipes, vape pipes, vaping pens, e-hookahs, and hookah pens.
Have you ever used an electronic vapor product?
• Yes
• No
Electronic vapor products, such as blu, NJOY, or Starbuzz, include e-cigarettes, e-cigars, e-pipes, vape pipes, vaping pens, e-hookahs, and hookah pens.
During the past 30 days, on how many days did you use an electronic vapor product?
• 0 days
• 1 or 2 days
• 3 to 5 days
• 6 to 9 days
• 10 to 19 days
• 20 to 29 days
• All 30 days
61 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Moore 2015
Electronic-cigarette use among young people in Wales: evidence from two cross-sectional surveys
Data from two data sets: the CHild Exposure to Tobacco Smoke (CHETS) survey undertaken in Wales (‘CHETS Wales 2’) in 2014; and 2014 Welsh Health Behaviour in School-aged Children (HBSC) Survey (‘HBSC Wales’).
In CHETS Wales 2, children were asked if they had ever used an e-cigarette, with response options of:
• ‘no’; ‘yes, once’; or
• ‘yes more than once’.
In HBSC Wales, young people were asked if they had ever used an e-cigarette, with at least once a month response options of: ‘I have never used or tried e-cigarettes’; ‘I have used e-cigarettes on a few occasions (1–5 times)’; or ‘I regularly use e-cigarettes (at least once a month)’
Those who selected using cigarettes at least once a month were classed as regular users
National Services Scotland 2014 Scottish Schools Adolescent Lifestyle and Substance Use Survey (SALSUS): SMOKING Among 13 and 15 year olds in Scotland 2013
2013/2014 Scottish Schools Adolescent Lifestyle and Substance Use Survey (SALSUS)
An electronic cigarette (sometimes called an ‘e-cigarette’) is a tube that can look like a normal cigarette, can have a glowing tip and puffs a vapour that looks like smoke but unlike normal cigarettes, they don’t burn tobacco. Now read the following statements carefully and cross the box next to the ONE which best describes you
• I have never used an e-cigarette
• I used to use e-cigarettes but don’t use them anymore
• I have tried an e-cigarette once
• I have tried e-cigarettes a few times
An electronic cigarette (sometimes called an ‘e-cigarette’) is a tube that can look like a normal cigarette, can have a glowing tip and puffs a vapour that looks like smoke but unlike normal cigarettes, they don’t burn tobacco. Now read the following statements carefully and cross the box next to the ONE which best describes you
• I use e-cigarettes sometimes, but no more than once a month
• I use e-cigarettes more than once a month, but less than once a week
• I use e-cigarettes once a week or more
62 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Citation Survey name/ Database
Ever e-cigarettes user measure
Current e-cigarettes user measure
Pepper 2013
Adolescent males’ awareness of and willingness to try electronic cigarettes
Knowledge Networks’ Knowledge Panel
Have you ever used an e-cigarette?
• Yes
• No
Not assessed
Porter 2015
Electronic cigarette and traditional cigarette use among middle and high school students in Florida, 2011-2014
Data are from the annual 2011–2014 Florida Youth Tobacco Survey (FYTS)
Have you ever tried once using electronic cigarettes?
• Yes
• No
During the past 30 days have you used an electronic cigarette?
• Yes
• No
Reid 2015
Tobacco Use in Canada: Patterns and Trends, 2015 Edition.
2015 Canadian Tobacco, Alcohol and Drugs Survey (CTADS)
Have you ever tried an electronic cigarette, also known as an e-cigarette?
• Yes
• No
In the past 30 days did you use an electronic cigarette, also known as an e-cigarette?
• Yes
• No
Surís 2015
Reasons to use e-cigarettes and associations with other substances among adolescents in Switzerland
Data were drawn from ado @ internet.ch, a longitudinal study on Internet use based on a representative sample of students in the French- speaking part of Switzerland.
Have you ever tried electronic cigarettes?
• Never
• Only once
• Several times
• Regularly
Those who selected ‘only once’ were classed as experimenters.
Have you ever tried electronic cigarettes?
• Never
• Only once
• Several times
• Regularly
Those who selected ‘several times’ and ‘regularly’ were classed as users.
Wang 2015
Electronic cigarette use and its association with smoking in Hong Kong Chinese adolescents
A 2012-2013, anonymous, self- administered questionnaire in Chinese adapted from the Global Youth Tobacco Survey (GYTS) (The GTSS Collaborative Group, 2006)
Not assessed Only one questions on e-cigarettes use in the past 30 days (yes vs no) was used. No levels of use were specified and students were expected to report any use including even 1 puff.
White 2015
Tripling Use of Electronic Cigarettes Among New Zealand Adolescents Between 2012 and 2014
2012 & 2014 The Youth Insights Survey
Have you ever tried electronic cigarettes?
• Yes
• No
Not assessed
63 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Annex 4: List of FiguresFigure 1: PRISMA diagram outlining study selection forprevalence of e-cigarette use (Objective 1)
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
For more information, visit www.prisma-statement.org.
Figure 1: PRISMA diagram outlining study selection for prevalence of e-cigarette use (Objective 1)
Records identified through database searching
(n = 3547 )
Scre
enin
g In
clud
ed
Elig
ibili
ty
Iden
tific
atio
n
Additional records identified through other sources
(n = 35)
Records after duplicates removed (n = 2281)
Records screened (n = 2281)
Records excluded (n = 2146)
Full-text articles assessed for eligibility
(n = 135)
Full-text articles excluded, with reasons
(n = 107) Adults (n=55) Did not report on prevalence of e-cigarette use (n=4) Did not use probability sampling (n=4) Not representativie of the region (n=14) Not an empirical study (n=12) Included findings previously reported in other published papers (n=18)
Studies included in qualitative synthesis
(n = 28)
Studies included in quantitative synthesis
(meta-analysis) (n = 28)
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for
Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/
journal.pmed1000097
For more information, visit www.prisma-statement.org.
64 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 2: PRISMA diagram outlining study selection forassociation of e-cigarette use and tobacco uptake (Objective 2)
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for
Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/
journal.pmed1000097
For more information, visit www.prisma-statement.org.
From: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097
For more information, visit www.prisma-statement.org.
Figure 2: PRISMA diagram outlining study selection for association of e-cigarette use and tobacco uptake (Objective 2)
Records identified through database searching
(n = 3547 )
Scre
enin
g In
clud
ed
Elig
ibili
ty
Iden
tific
atio
n
Additional records identified through other sources
(n = 35)
Records after duplicates removed (n = 2281)
Records screened (n = 2281)
Records excluded (n = 2162)
Full-text articles assessed for eligibility
(n = 119)
Full-text articles excluded, with reasons
(n = 116) Did not examine e-cigarette use (n=5) Not undertaken in youth/adolescents (n=5) Did not examine association with tobacco/cigarette smoking (n=26) Conference abstract of published study (n=1) Not relevant study design (n=79)
Studies included in qualitative synthesis
(n = 3 )
Studies included in quantitative synthesis
(meta-analysis) (n = 3 )
65 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 3: Quality assessment for individual cross-sectional studies included for Objective 1
*Eastwood 2014, Ford 2015, Suris
2015, West 2012 were included in
the sensitivity analyses.
Yes No Unsure
66 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 4: Quality assessment for individual longitudinal studies included for Objective 2
Figu
re 5
: Poo
led
anal
ysis
of e
ver e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Yes No Unsure
67 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 5
: Poo
led
anal
ysis
of e
ver e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
)
Kris
tjans
son
Moo
re
Port
er
Alas
ka
Port
er
Gallu
s
Barn
ett
Arra
zola
Mon
tana
Goni
ewic
z
SALS
US
Fotio
u
Anan
d
Gallu
s
Gallu
s
Moo
re
Arra
zola
Babi
neau
Li Ham
ilton
Whi
te
Auth
or
Reid
Icel
and
UK
(Wal
es)
US
(Flo
rida)
US
(Ala
ska)
US
(Flo
rida)
Ital
y
US
(Flo
rida)
US
NYT
S
US
(Mon
tana
)
Pola
nd
UK
(Sco
tlan
d)
Gree
ce
US
(Cal
iforn
ia)
Ital
y
Ital
y
UK
(Wal
es)
US
NYT
S
Irel
and
New
Zea
land
Cana
da (O
ntar
io)
New
Zea
land
Coun
try
Cana
da
2015
2014
2014
2015
2014
2015
2013
2013
2015
2013
-201
4
2013
-201
4
2014
2013
2013
2014
2014
2013
2014
2014
2015
2014
colle
ctio
n
2013
Dat
a
15-1
6
10-1
1
15-1
8
14-1
8
11-1
4
16-1
9
11-1
8
11-1
4
14-1
8
15-1
9
13-1
5
1515-1
8
16-1
9
16-1
9
11-1
6
15-1
8
16-1
7
15-1
7
14-1
8
14-1
5
rang
e
15-1
9
Age
3477
1601
3292
1
1418
3697
9
160
1261
5
8111
4486
1970
3205
1
1320
2769
163
153
9055
1019
0
821
99 2892
2919
N 1658
6
587
87 6749
512
3143
71098
243
2292
1223
3487
219
421
15 7 1018
1213
196
20 422
584
(n)
3284
Out
com
e
16.4
(12.
5, 2
0.6)
16.9
(15.
7, 1
8.2)
5.4
(4.4
, 6.7
)
20.5
(20.
1, 2
0.9)
36.1
(33.
6, 3
8.7)
8.5
(8.2
, 8.8
)
4.4
(1.8
, 8.8
)
8.7
(8.2
, 9.2
)
3.0
(2.6
, 3.4
)
51.1
(49.
6, 5
2.6)
62.1
(59.
9, 6
4.2)
10.9
(10.
5, 1
1.2)
16.6
(14.
6, 1
8.7)
15.2
(13.
9, 1
6.6)
9.2
(5.2
, 14.
7)
4.6
(1.9
, 9.2
)
11.2
(10.
6, 1
1.9)
11.9
(11.
3, 1
2.5)
23.9
(21.
0, 2
6.9)
20.2
(12.
8, 2
9.5)
14.6
(13.
3, 1
5.9)
20.0
(18.
6, 2
1.5)
ES (9
5% C
I)
19.8
(19.
2, 2
0.4)
16.4
(12.
5, 2
0.6)
16.9
(15.
7, 1
8.2)
5.4
(4.4
, 6.7
)
20.5
(20.
1, 2
0.9)
36.1
(33.
6, 3
8.7)
8.5
(8.2
, 8.8
)
4.4
(1.8
, 8.8
)
8.7
(8.2
, 9.2
)
3.0
(2.6
, 3.4
)
51.1
(49.
6, 5
2.6)
62.1
(59.
9, 6
4.2)
10.9
(10.
5, 1
1.2)
16.6
(14.
6, 1
8.7)
15.2
(13.
9, 1
6.6)
9.2
(5.2
, 14.
7)
4.6
(1.9
, 9.2
)
11.2
(10.
6, 1
1.9)
11.9
(11.
3, 1
2.5)
23.9
(21.
0, 2
6.9)
20.2
(12.
8, 2
9.5)
14.6
(13.
3, 1
5.9)
20.0
(18.
6, 2
1.5)
ES (9
5% C
I)
19.8
(19.
2, 2
0.4)
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 6
: Sen
sitiv
ity a
naly
sis
of e
ver e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
)
Barn
ett [
US
(Flo
rida)
, 201
3]
East
woo
d [U
K (E
ngla
nd),
2014
]
Moo
re [U
K (W
ales
), 20
14]
Babi
neau
[Ire
land
, 201
4]
Arra
zola
[US
NYT
S, 2
013]
Gallu
s [It
aly,
201
3]
Gallu
s [It
aly,
201
5]
Ham
ilton
[Can
ada
(Ont
ario
), 20
15]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
Arra
zola
[US
NYT
S, 2
013]
Kris
tjans
son
[Icel
and,
201
5]
Ford
[UK
(Eng
land
), 20
15]
Alas
ka [U
S (A
lask
a), 2
015]
Whi
te [N
ew Z
eala
nd, 2
014]
Suris
[Sw
itzer
land
, 201
5]
Mon
tana
[US
(Mon
tana
), 20
15]
Gallu
s [It
aly,
201
4]
Port
er [U
S (F
lorid
a), 2
014]
Sour
ce
Port
er [U
S (F
lorid
a), 2
014]
Moo
re [U
K (W
ales
), 20
14]
Fotio
u [G
reec
e, 2
014]
Li [N
ew Z
eala
nd, 2
014]
Goni
ewic
z [P
olan
d, 2
013-
2014
]
East
woo
d [U
K (E
ngla
nd),
2013
]
Anan
d [U
S (C
alifo
rnia
), 20
13]
Reid
[Can
ada,
201
3]
11-1
8
11-1
8
10-1
1
16-1
7
15-1
8
16-1
9
16-1
9
14-1
8
13-1
5
11-1
4
15-1
6
11-1
6
14-1
8
14-1
5
16 14-1
8
16-1
9
11-1
4
rang
e
15-1
8
11-1
6
15 15-1
7
15-1
9
11-1
8
15-1
8
15-1
9
Age
1098
170
87196
1213
15 7422
3487
243
587
145
512
584
267
2292
7 3143
(n)
6749
1018
219
201223
100
421
3284
Out
com
e
1261
5
2068
1601
821
1019
0
163
160
2892
3205
1
8111
3477
1205
1418
2919
621
4486
153
3697
9
part
icip
ants
3292
1
9055
1320
991970
2177
2769
1658
6
Num
ber o
f
16.1
(12.
6, 2
0.0)
8.7
(8.2
, 9.2
)
8.2
(7.1
, 9.5
)
5.4
(4.4
, 6.7
)
23.9
(21.
0, 2
6.9)
11.9
(11.
3, 1
2.5)
9.2
(5.2
, 14.
7)
4.4
(1.8
, 8.8
)
14.6
(13.
3, 1
5.9)
10.9
(10.
5, 1
1.2)
3.0
(2.6
, 3.4
)
16.9
(15.
7, 1
8.2)
12.0
(10.
2, 1
4.0)
36.1
(33.
6, 3
8.7)
20.0
(18.
6, 2
1.5)
43.0
(39.
1, 4
7.0)
51.1
(49.
6, 5
2.6)
4.6
(1.9
, 9.2
)
8.5
(8.2
, 8.8
)
ES (9
5% C
I)
20.5
(20.
1, 2
0.9)
11.2
(10.
6, 1
1.9)
16.6
(14.
6, 1
8.7)
20.2
(12.
8, 2
9.5)
62.1
(59.
9, 6
4.2)
4.6
(3.8
, 5.6
)
15.2
(13.
9, 1
6.6)
19.8
(19.
2, 2
0.4)
100.
00
3.92
3.90
3.89
3.86
3.92
3.60
3.59
3.91
3.92
3.92
3.91
3.88
3.88
3.91
3.83
3.91
3.58
3.92
Wei
ght
3.92
3.92
3.88
3.41
3.90
3.90
3.90
3.92
%
16.1
(12.
6, 2
0.0)
8.7
(8.2
, 9.2
)
8.2
(7.1
, 9.5
)
5.4
(4.4
, 6.7
)
23.9
(21.
0, 2
6.9)
11.9
(11.
3, 1
2.5)
9.2
(5.2
, 14.
7)
4.4
(1.8
, 8.8
)
14.6
(13.
3, 1
5.9)
10.9
(10.
5, 1
1.2)
3.0
(2.6
, 3.4
)
16.9
(15.
7, 1
8.2)
12.0
(10.
2, 1
4.0)
36.1
(33.
6, 3
8.7)
20.0
(18.
6, 2
1.5)
43.0
(39.
1, 4
7.0)
51.1
(49.
6, 5
2.6)
4.6
(1.9
, 9.2
)
8.5
(8.2
, 8.8
)
ES (9
5% C
I)
20.5
(20.
1, 2
0.9)
11.2
(10.
6, 1
1.9)
16.6
(14.
6, 1
8.7)
20.2
(12.
8, 2
9.5)
62.1
(59.
9, 6
4.2)
4.6
(3.8
, 5.6
)
15.2
(13.
9, 1
6.6)
19.8
(19.
2, 2
0.4)
100.
00
3.92
3.90
3.89
3.86
3.92
3.60
3.59
3.91
3.92
3.92
3.91
3.88
3.88
3.91
3.83
3.91
3.58
3.92
Wei
ght
3.92
3.92
3.88
3.41
3.90
3.90
3.90
3.92
%
010
2030
4060
80
Heterogeneity between groups: p = 0.000Overall (I^2 = 99.8%, p = 0.0);
Subtotal (I^2 = 99.9%, p = 0.0)
Porter
Reid
Goniewicz
Iceland
Corey
Porter
Korea
Gallus
Subtotal (I^2 = 45.9%, p = 0.2)
US
Corey
Poland
Gallus
Arrazola
Greece
Anand
Moore
Goniewicz
Li
Montana
Lee
Hamilton
Barnett
Ireland
Subtotal (I^2 = 96.9%, p = 0.0)
Alaska
Subtotal (I^2 = 99.2%, p = 0.0)
Gallus
Porter
WhiteNew Zealand
Cho
Subtotal (I^2 = 72.9%, p = 0.1)
Kristjansson
Arrazola
White
SALSUSUK
Canada (Ontario)
Corey
Babineau
Fotiou
Porter
PorterCoreyPorter
Moore
Canada
DautzenbergFrance
Pepper
Subtotal (I^2 = 99.6%, p = 0.0)
Author
Italy
US (Florida)
Canada
Poland
US NYTS
US (Florida)
Italy
US NYTS
Italy
US NYTSUS (California)
UK (Wales)
Poland
New Zealand
US (Montana)
Korea
Canada (Ontario)
US (Florida)
US (Alaska)
Italy
US (Florida)
New Zealand
Korea
Iceland
US NYTS
New Zealand
UK (Scotland)
US NYTS
Ireland
Greece
US (Florida)
US (Florida)US NYTSUS (Florida)
UK (Wales)
France (Paris)
US National
Country
2014
2013
2010-2011
2012
2011
2014
2011
2015
20132013
2014
2013-2014
2014
2015
2011
2015
2013
2015
2013
2011
2012
2008
2015
2013
2014
2013-2014
2011
2014
2014
2014
2012
Data
20122012
2014
2012
2011
collection
15-18
15-19
15-24
15-18
15-18
16-19
15-18
16-19
15-1815-18
11-16
15-19
15-17
14-18
13-18
14-18
11-18
14-18
16-19
11-14
14-15
13-19
15-16
11-14
14-15
13-15
11-14
16-17
15
11-14
11-14
Age
11-1415-18
10-11
12-19
12-18
range
32921
16586
13787
12899
6163
153
9720
160
101902769
9055
1970
99
4486
75643
2892
12615
1418
163
6045
3127
4341
3477
8111
2919
32051
8880
821
1320
36979
369891166736439
1601
3409
228
N
6749
3284
2881
1290
370
7
457
7
1213421
1018
1223
20
2292
7110
422
1098
512
15
181
219
22
587
243
584
3487
124
196
219
3143
1443
Outcome
3153061
87
277
2
(n)
11.4 (9.0, 14.0)
9.3 (6.1, 13.2)
20.5 (20.1, 20.9)
19.8 (19.2, 20.4)
20.9 (20.2, 21.6)
10.0 (9.5, 10.5)
6.0 (5.4, 6.6)
4.6 (1.9, 9.2)
5.9 (3.3, 9.2)
4.7 (4.3, 5.1)
4.4 (1.8, 8.8)
11.9 (11.3, 12.5)15.2 (13.9, 16.6)
11.2 (10.6, 11.9)
62.1 (59.9, 64.2)
20.2 (12.8, 29.5)
51.1 (49.6, 52.6)
9.4 (9.2, 9.6)
14.6 (13.3, 15.9)
8.7 (8.2, 9.2)
9.2 (7.2, 11.3)
36.1 (33.6, 38.7)
14.9 (5.5, 27.7)
9.2 (5.2, 14.7)
3.0 (2.6, 3.5)
7.0 (6.1, 8.0)
0.5 (0.3, 0.8)
8.6 (8.5, 8.8)
16.9 (15.7, 18.2)
3.0 (2.6, 3.4)
20.0 (18.6, 21.5)
10.9 (10.5, 11.2)
1.4 (1.2, 1.7)
23.9 (21.0, 26.9)
16.6 (14.6, 18.7)
8.5 (8.2, 8.8)
3.9 (3.7, 4.1)2.7 (2.4, 3.0)8.4 (8.1, 8.7)
5.4 (4.4, 6.7)
8.1 (7.2, 9.1)
0.9 (0.1, 3.1)
25.5 (24.8, 26.1)
ES (95% CI)
11.4 (9.0, 14.0)
9.3 (6.1, 13.2)
20.5 (20.1, 20.9)
19.8 (19.2, 20.4)
20.9 (20.2, 21.6)
10.0 (9.5, 10.5)
6.0 (5.4, 6.6)
4.6 (1.9, 9.2)
5.9 (3.3, 9.2)
4.7 (4.3, 5.1)
4.4 (1.8, 8.8)
11.9 (11.3, 12.5)15.2 (13.9, 16.6)
11.2 (10.6, 11.9)
62.1 (59.9, 64.2)
20.2 (12.8, 29.5)
51.1 (49.6, 52.6)
9.4 (9.2, 9.6)
14.6 (13.3, 15.9)
8.7 (8.2, 9.2)
9.2 (7.2, 11.3)
36.1 (33.6, 38.7)
14.9 (5.5, 27.7)
9.2 (5.2, 14.7)
3.0 (2.6, 3.5)
7.0 (6.1, 8.0)
0.5 (0.3, 0.8)
8.6 (8.5, 8.8)
16.9 (15.7, 18.2)
3.0 (2.6, 3.4)
20.0 (18.6, 21.5)
10.9 (10.5, 11.2)
1.4 (1.2, 1.7)
23.9 (21.0, 26.9)
16.6 (14.6, 18.7)
8.5 (8.2, 8.8)
3.9 (3.7, 4.1)2.7 (2.4, 3.0)8.4 (8.1, 8.7)
5.4 (4.4, 6.7)
8.1 (7.2, 9.1)
0.9 (0.1, 3.1)
25.5 (24.8, 26.1)
ES (95% CI)
0 10 20 30 40 60 80
69 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figure 7: Pooled analysis of ever e-cigarette use among youth by country (2008-2015)
Heterogeneity between groups: p = 0.000Overall (I^2 = 99.8%, p = 0.0);
Subtotal (I^2 = 99.9%, p = 0.0)
Porter
Reid
Goniewicz
Iceland
Corey
Porter
Korea
Gallus
Subtotal (I^2 = 45.9%, p = 0.2)
US
Corey
Poland
Gallus
Arrazola
Greece
Anand
Moore
Goniewicz
Li
Montana
Lee
Hamilton
Barnett
Ireland
Subtotal (I^2 = 96.9%, p = 0.0)
Alaska
Subtotal (I^2 = 99.2%, p = 0.0)
Gallus
Porter
WhiteNew Zealand
Cho
Subtotal (I^2 = 72.9%, p = 0.1)
Kristjansson
Arrazola
White
SALSUSUK
Canada (Ontario)
Corey
Babineau
Fotiou
Porter
PorterCoreyPorter
Moore
Canada
DautzenbergFrance
Pepper
Subtotal (I^2 = 99.6%, p = 0.0)
Author
Italy
US (Florida)
Canada
Poland
US NYTS
US (Florida)
Italy
US NYTS
Italy
US NYTSUS (California)
UK (Wales)
Poland
New Zealand
US (Montana)
Korea
Canada (Ontario)
US (Florida)
US (Alaska)
Italy
US (Florida)
New Zealand
Korea
Iceland
US NYTS
New Zealand
UK (Scotland)
US NYTS
Ireland
Greece
US (Florida)
US (Florida)US NYTSUS (Florida)
UK (Wales)
France (Paris)
US National
Country
2014
2013
2010-2011
2012
2011
2014
2011
2015
20132013
2014
2013-2014
2014
2015
2011
2015
2013
2015
2013
2011
2012
2008
2015
2013
2014
2013-2014
2011
2014
2014
2014
2012
Data
20122012
2014
2012
2011
collection
15-18
15-19
15-24
15-18
15-18
16-19
15-18
16-19
15-1815-18
11-16
15-19
15-17
14-18
13-18
14-18
11-18
14-18
16-19
11-14
14-15
13-19
15-16
11-14
14-15
13-15
11-14
16-17
15
11-14
11-14
Age
11-1415-18
10-11
12-19
12-18
range
32921
16586
13787
12899
6163
153
9720
160
101902769
9055
1970
99
4486
75643
2892
12615
1418
163
6045
3127
4341
3477
8111
2919
32051
8880
821
1320
36979
369891166736439
1601
3409
228
N
6749
3284
2881
1290
370
7
457
7
1213421
1018
1223
20
2292
7110
422
1098
512
15
181
219
22
587
243
584
3487
124
196
219
3143
1443
Outcome
3153061
87
277
2
(n)
11.4 (9.0, 14.0)
9.3 (6.1, 13.2)
20.5 (20.1, 20.9)
19.8 (19.2, 20.4)
20.9 (20.2, 21.6)
10.0 (9.5, 10.5)
6.0 (5.4, 6.6)
4.6 (1.9, 9.2)
5.9 (3.3, 9.2)
4.7 (4.3, 5.1)
4.4 (1.8, 8.8)
11.9 (11.3, 12.5)15.2 (13.9, 16.6)
11.2 (10.6, 11.9)
62.1 (59.9, 64.2)
20.2 (12.8, 29.5)
51.1 (49.6, 52.6)
9.4 (9.2, 9.6)
14.6 (13.3, 15.9)
8.7 (8.2, 9.2)
9.2 (7.2, 11.3)
36.1 (33.6, 38.7)
14.9 (5.5, 27.7)
9.2 (5.2, 14.7)
3.0 (2.6, 3.5)
7.0 (6.1, 8.0)
0.5 (0.3, 0.8)
8.6 (8.5, 8.8)
16.9 (15.7, 18.2)
3.0 (2.6, 3.4)
20.0 (18.6, 21.5)
10.9 (10.5, 11.2)
1.4 (1.2, 1.7)
23.9 (21.0, 26.9)
16.6 (14.6, 18.7)
8.5 (8.2, 8.8)
3.9 (3.7, 4.1)2.7 (2.4, 3.0)8.4 (8.1, 8.7)
5.4 (4.4, 6.7)
8.1 (7.2, 9.1)
0.9 (0.1, 3.1)
25.5 (24.8, 26.1)
ES (95% CI)
11.4 (9.0, 14.0)
9.3 (6.1, 13.2)
20.5 (20.1, 20.9)
19.8 (19.2, 20.4)
20.9 (20.2, 21.6)
10.0 (9.5, 10.5)
6.0 (5.4, 6.6)
4.6 (1.9, 9.2)
5.9 (3.3, 9.2)
4.7 (4.3, 5.1)
4.4 (1.8, 8.8)
11.9 (11.3, 12.5)15.2 (13.9, 16.6)
11.2 (10.6, 11.9)
62.1 (59.9, 64.2)
20.2 (12.8, 29.5)
51.1 (49.6, 52.6)
9.4 (9.2, 9.6)
14.6 (13.3, 15.9)
8.7 (8.2, 9.2)
9.2 (7.2, 11.3)
36.1 (33.6, 38.7)
14.9 (5.5, 27.7)
9.2 (5.2, 14.7)
3.0 (2.6, 3.5)
7.0 (6.1, 8.0)
0.5 (0.3, 0.8)
8.6 (8.5, 8.8)
16.9 (15.7, 18.2)
3.0 (2.6, 3.4)
20.0 (18.6, 21.5)
10.9 (10.5, 11.2)
1.4 (1.2, 1.7)
23.9 (21.0, 26.9)
16.6 (14.6, 18.7)
8.5 (8.2, 8.8)
3.9 (3.7, 4.1)2.7 (2.4, 3.0)8.4 (8.1, 8.7)
5.4 (4.4, 6.7)
8.1 (7.2, 9.1)
0.9 (0.1, 3.1)
25.5 (24.8, 26.1)
ES (95% CI)
0 10 20 30 40 60 80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 9
: Sen
sitiv
ity a
naly
sis
of c
urre
nt e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Figu
re 8
: Poo
led
anal
ysis
of c
urre
nt e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
)
Gallu
s
Arra
zola
John
ston
Gallu
s
Reid
Gallu
s
Mon
tana
Alas
ka
Port
er
Fotio
u
Arra
zola
Anan
d
Port
er
Moo
re
Babi
neau
Auth
or
Arra
zola
SALS
US
Arra
zola
Barn
ett
Goni
ewic
z
Hun
gary
Li
Ital
y
US
NYT
S
US
Ital
y
Cana
da
Ital
y
US
(Mon
tana
)
US
(Ala
ska)
US
(Flo
rida)
Gree
ce
US
NYT
S
US
(Cal
iforn
ia)
US
(Flo
rida)
UK
(Wal
es)
Irel
and
Coun
try
US
NYT
S
UK
(Sco
tlan
d)
US
NYT
S
US
(Flo
rida)
Pola
nd
Hun
gary
New
Zea
land
2013
2013
2014
2014
2013
2015
2015
2015
2014
2014
2014
2013
2014
2014
2014
colle
ctio
n
2014
2013
-201
4
2013
2013
2013
-201
4
2013
2014
Dat
a
16-1
9
15-1
8
13-1
8
16-1
9
15-1
9
16-1
9
14-1
8
14-1
8
11-1
4
15 15-1
8
15-1
8
15-1
8
11-1
6
16-1
7
rang
e
11-1
4
13-1
5
11-1
4
11-1
8
15-1
9
13-1
5
15-1
7
Age
163
1019
0
4160
0
153
1658
6
160
4486
1418
3697
9
1320
1145
9
2769
3292
1
9022
821
N 1041
9
3205
1
8111
1261
5
1970
4018
99
3 459
5782
1431
2 1323
251
1479
7 1536
205
3555
125
26(n)
406
276
89492
589
362
0Out
com
e
5.6
(3.4
, 8.3
)
1.8
(0.4
, 5.3
)
4.5
(4.1
, 4.9
)
13.9
(13.
6, 1
4.2)
0.7
(0.0
, 3.6
)
2.6
(2.4
, 2.9
)
1.3
(0.2
, 4.4
)
29.5
(28.
2, 3
0.9)
17.7
(15.
7, 1
9.8)
4.0
(3.8
, 4.2
)
0.5
(0.2
, 1.1
)
13.4
(12.
8, 1
4.0)
7.4
(6.5
, 8.4
)
10.8
(10.
5, 1
1.1)
1.4
(1.2
, 1.6
)
3.2
(2.1
, 4.6
)
ES (9
5% C
I)
3.9
(3.5
, 4.3
)
0.9
(0.8
, 1.0
)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
29.9
(27.
9, 3
2.0)
9.0
(8.1
, 9.9
)
0.0
(0.0
, 3.7
)
5.6
(3.4
, 8.3
)
1.8
(0.4
, 5.3
)
4.5
(4.1
, 4.9
)
13.9
(13.
6, 1
4.2)
0.7
(0.0
, 3.6
)
2.6
(2.4
, 2.9
)
1.3
(0.2
, 4.4
)
29.5
(28.
2, 3
0.9)
17.7
(15.
7, 1
9.8)
4.0
(3.8
, 4.2
)
0.5
(0.2
, 1.1
)
13.4
(12.
8, 1
4.0)
7.4
(6.5
, 8.4
)
10.8
(10.
5, 1
1.1)
1.4
(1.2
, 1.6
)
3.2
(2.1
, 4.6
)
ES (9
5% C
I)
3.9
(3.5
, 4.3
)
0.9
(0.8
, 1.0
)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
29.9
(27.
9, 3
2.0)
9.0
(8.1
, 9.9
)
0.0
(0.0
, 3.7
)
010
2030
40
71 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 9
: Sen
sitiv
ity a
naly
sis
of c
urre
nt e
-cig
aret
te u
se a
mon
g yo
uth
from
201
3-20
15
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
)
Gallu
s
Arra
zola
John
ston
Gallu
s
Reid
Gallu
s
Mon
tana
Alas
ka
Port
er
Fotio
u
Arra
zola
Anan
d
Port
er
Moo
re
Babi
neau
Auth
or
Arra
zola
SALS
US
Arra
zola
Barn
ett
Goni
ewic
z
Hun
gary
Li
Ital
y
US
NYT
S
US
Ital
y
Cana
da
Ital
y
US
(Mon
tana
)
US
(Ala
ska)
US
(Flo
rida)
Gree
ce
US
NYT
S
US
(Cal
iforn
ia)
US
(Flo
rida)
UK
(Wal
es)
Irel
and
Coun
try
US
NYT
S
UK
(Sco
tlan
d)
US
NYT
S
US
(Flo
rida)
Pola
nd
Hun
gary
New
Zea
land
2013
2013
2014
2014
2013
2015
2015
2015
2014
2014
2014
2013
2014
2014
2014
colle
ctio
n
2014
2013
-201
4
2013
2013
2013
-201
4
2013
2014
Dat
a
16-1
9
15-1
8
13-1
8
16-1
9
15-1
9
16-1
9
14-1
8
14-1
8
11-1
4
15 15-1
8
15-1
8
15-1
8
11-1
6
16-1
7
rang
e
11-1
4
13-1
5
11-1
4
11-1
8
15-1
9
13-1
5
15-1
7
Age
163
1019
0
4160
0
153
1658
6
160
4486
1418
3697
9
1320
1145
9
2769
3292
1
9022
821
N 1041
9
3205
1
8111
1261
5
1970
4018
99
3 459
5782
1431
2 1323
251
1479
7 1536
205
3555
125
26(n)
406
276
89492
589
362
0Out
com
e
5.6
(3.4
, 8.3
)
1.8
(0.4
, 5.3
)
4.5
(4.1
, 4.9
)
13.9
(13.
6, 1
4.2)
0.7
(0.0
, 3.6
)
2.6
(2.4
, 2.9
)
1.3
(0.2
, 4.4
)
29.5
(28.
2, 3
0.9)
17.7
(15.
7, 1
9.8)
4.0
(3.8
, 4.2
)
0.5
(0.2
, 1.1
)
13.4
(12.
8, 1
4.0)
7.4
(6.5
, 8.4
)
10.8
(10.
5, 1
1.1)
1.4
(1.2
, 1.6
)
3.2
(2.1
, 4.6
)
ES (9
5% C
I)
3.9
(3.5
, 4.3
)
0.9
(0.8
, 1.0
)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
29.9
(27.
9, 3
2.0)
9.0
(8.1
, 9.9
)
0.0
(0.0
, 3.7
)
5.6
(3.4
, 8.3
)
1.8
(0.4
, 5.3
)
4.5
(4.1
, 4.9
)
13.9
(13.
6, 1
4.2)
0.7
(0.0
, 3.6
)
2.6
(2.4
, 2.9
)
1.3
(0.2
, 4.4
)
29.5
(28.
2, 3
0.9)
17.7
(15.
7, 1
9.8)
4.0
(3.8
, 4.2
)
0.5
(0.2
, 1.1
)
13.4
(12.
8, 1
4.0)
7.4
(6.5
, 8.4
)
10.8
(10.
5, 1
1.1)
1.4
(1.2
, 1.6
)
3.2
(2.1
, 4.6
)
ES (9
5% C
I)
3.9
(3.5
, 4.3
)
0.9
(0.8
, 1.0
)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
29.9
(27.
9, 3
2.0)
9.0
(8.1
, 9.9
)
0.0
(0.0
, 3.7
)
010
2030
40
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
)
Moo
re [U
K (W
ales
), 20
14]
Gallu
s [It
aly,
201
4]
Anan
d [U
S (C
alifo
rnia
), 20
13]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
Fotio
u [G
reec
e, 2
014]
Arra
zola
[US
NYT
S, 2
014]
Alas
ka [U
S (A
lask
a), 2
015]
Reid
[Can
ada,
201
3]
Port
er [U
S (F
lorid
a), 2
014]
Gallu
s [It
aly,
201
3]
Babi
neau
[Ire
land
, 201
4]
Gallu
s [It
aly,
201
5]
East
woo
d [U
K (E
ngla
nd),
2014
]
Li [N
ew Z
eala
nd, 2
014]
John
ston
[US,
201
4]
Arra
zola
[US
NYT
S, 2
014]
Smok
ing
[UK
(Eng
land
), 20
14]
Suris
[Sw
itzer
land
, 201
5]
Smok
ing
[UK
(Eng
land
), 20
15]
Goni
ewic
z [P
olan
d, 2
013-
2014
]
Arra
zola
[US
NYT
S, 2
013]
Barn
ett [
US
(Flo
rida)
, 201
3]
Hun
gary
[Hun
gary
, 201
3]
East
woo
d [U
K (E
ngla
nd),
2013
]
Mon
tana
[US
(Mon
tana
), 20
15]
Port
er [U
S (F
lorid
a), 2
014]
Arra
zola
[US
NYT
S, 2
013]
Sour
ce
11-1
6
16-1
9
15-1
8
13-1
5
15 11-1
4
14-1
8
15-1
9
Age
11-1
4
16-1
9
16-1
7
16-1
9
11-1
8
15-1
7
13-1
8
15-1
8
16-2
0
16 16-2
0
15-1
9
11-1
4
11-1
8
13-1
5
14-1
8
15-1
8
15-1
8
rang
e
125
1205
276
7 406
251
431
Out
com
e
1479
3 26 2350 5782
1536
49 149
69589
89492
362
16 1323
3555
459
(n)
9022
153
2769
3205
1
1320
1041
9
1418
1658
6
Num
ber o
f
3697
9
163
821
160
2068
99 4160
0
1145
9
1405
621
1332
1970
8111
1261
5
4018
2177
4486
3292
1
1019
0
part
icip
ants
5.5
(3.5
, 7.9
)
1.4
(1.2
, 1.6
)
0.7
(0.0
, 3.6
)
7.4
(6.5
, 8.4
)
0.9
(0.8
, 1.0
)
0.5
(0.2
, 1.1
)
3.9
(3.5
, 4.3
)
17.7
(15.
7, 1
9.8)
2.6
(2.4
, 2.9
)
4.0
(3.8
, 4.2
)
1.8
(0.4
, 5.3
)
3.2
(2.1
, 4.6
)
1.3
(0.2
, 4.4
)
1.7
(1.2
, 2.3
)
0.0
(0.0
, 3.7
)
13.9
(13.
6, 1
4.2)
13.4
(12.
8, 1
4.0)
3.5
(2.6
, 4.6
)
24.0
(20.
7, 2
7.6)
5.2
(4.1
, 6.5
)
29.9
(27.
9, 3
2.0)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
9.0
(8.1
, 9.9
)
0.7
(0.4
, 1.2
)
29.5
(28.
2, 3
0.9)
10.8
(10.
5, 1
1.1)
4.5
(4.1
, 4.9
)
ES (9
5% C
I)
100.
00
3.77
3.42
3.76
3.78
3.74
3.77
3.74
3.78
% 3.78
3.44
3.71
3.44
3.75
3.26
3.78
3.78
3.74
3.69
3.74
3.75
3.77
3.78
3.77
3.75
3.77
3.78
3.77
Wei
ght
5.5
(3.5
, 7.9
)
1.4
(1.2
, 1.6
)
0.7
(0.0
, 3.6
)
7.4
(6.5
, 8.4
)
0.9
(0.8
, 1.0
)
0.5
(0.2
, 1.1
)
3.9
(3.5
, 4.3
)
17.7
(15.
7, 1
9.8)
2.6
(2.4
, 2.9
)
4.0
(3.8
, 4.2
)
1.8
(0.4
, 5.3
)
3.2
(2.1
, 4.6
)
1.3
(0.2
, 4.4
)
1.7
(1.2
, 2.3
)
0.0
(0.0
, 3.7
)
13.9
(13.
6, 1
4.2)
13.4
(12.
8, 1
4.0)
3.5
(2.6
, 4.6
)
24.0
(20.
7, 2
7.6)
5.2
(4.1
, 6.5
)
29.9
(27.
9, 3
2.0)
1.1
(0.9
, 1.3
)
3.9
(3.6
, 4.3
)
9.0
(8.1
, 9.9
)
0.7
(0.4
, 1.2
)
29.5
(28.
2, 3
0.9)
10.8
(10.
5, 1
1.1)
4.5
(4.1
, 4.9
)
ES (9
5% C
I)
100.
00
3.77
3.42
3.76
3.78
3.74
3.77
3.74
3.78
% 3.78
3.44
3.71
3.44
3.75
3.26
3.78
3.78
3.74
3.69
3.74
3.75
3.77
3.78
3.77
3.75
3.77
3.78
3.77
Wei
ght
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
1: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Heterogeneity between groups: p = 0.000Overall (I^2 = 99.8%, p = 0.0);
Author
Wang
Corey
Greece
Gallus
Babineau
Arrazola
Fotiou
Anand
Johnston
Gallus
Corey
Gallus
Subtotal (I^2 = 0.0%, p = 0.7)
Hungary
UK
Goniewicz
Reid
Porter
Poland
Italy
MooreSALSUS
Porter
Arrazola
Li
Hungary
ArrazolaPorter
Subtotal (I^2 = 100.0%, p = 0.0)
Korea
Corey
China (Hong Kong)
Canada
Ireland
Subtotal (I^2 = 0.0%, p = 0.4)
Arrazola
Porter
Montana
Porter
CoreyPorter
Alaska
Barnett
New Zealand
Lee
US
Subtotal (I^2 = 99.9%, p = 0.0)
Goniewicz
Hungary
Subtotal (I^2 = 100.0%, p = 0.0)
Country
China (Hong Kong)
US NYTS
Italy
Ireland
US NYTS
Greece
US (California)
US
Italy
US NYTS
Italy
Poland
Canada
US (Florida)
UK (Wales)UK (Scotland)
US (Florida)
US NYTS
New Zealand
Hungary
US NYTSUS (Florida)
US NYTS
US NYTS
US (Florida)
US (Montana)
US (Florida)
US NYTSUS (Florida)
US (Alaska)
US (Florida)
Korea
Poland
Hungary
collection
2012-2013
2012
Data
2015
2014
2013
2014
2013
2014
2013
2012
2014
2010-2011
2013
2011
20142013-2014
2012
2014
2014
2012
20142014
2011
2013
2012
2015
2014
20112011
2015
2013
2011
2013-2014
2013
range
12-18
15-18
Age
16-19
16-17
15-18
15
15-18
13-18
16-19
11-14
16-19
15-24
15-19
15-18
11-1613-15
15-18
11-14
15-17
13-15
15-1815-18
15-18
11-14
11-14
14-18
11-14
11-1411-14
14-18
11-18
13-18
15-19
13-15
N
45128
12899
160
821
10190
1320
2769
41600
163
11667
153
13787
16586
6163
902232051
36439
10419
99
2325
1145932921
9720
8111
36989
4486
36979
88806045
1418
12615
75643
1970
4018
(n)
496
361
Outcome
2
26
459
7
205
5782
3
128
1
1131
431
191
125276
1275
406
0
302
15363555
146
89
666
1323
1479
5391
251
492
3555
589
362
4.6 (3.2, 6.2)
ES (95% CI)
1.1 (1.0, 1.2)
2.8 (2.5, 3.1)
1.3 (0.2, 4.4)
3.2 (2.1, 4.6)
4.5 (4.1, 4.9)
0.5 (0.2, 1.1)
7.4 (6.5, 8.4)
13.9 (13.6, 14.2)
1.8 (0.4, 5.3)
1.1 (0.9, 1.3)
0.7 (0.0, 3.6)
1.2 (0.3, 2.5)
8.2 (7.8, 8.7)
2.6 (2.4, 2.9)
3.1 (2.7, 3.6)
1.4 (1.2, 1.6)0.9 (0.8, 1.0)
3.5 (3.3, 3.7)
3.9 (3.5, 4.3)
0.0 (0.0, 3.7)
13.0 (11.6, 14.4)
13.4 (12.8, 14.0)10.8 (10.5, 11.1)
10.4 (9.7, 11.2)
1.5 (1.3, 1.8)
1.0 (0.9, 1.1)
1.1 (0.9, 1.3)
1.8 (1.7, 1.9)
29.5 (28.2, 30.9)
4.0 (3.8, 4.2)
0.6 (0.4, 0.8)1.5 (1.2, 1.8)
17.7 (15.7, 19.8)
3.9 (3.6, 4.3)
4.7 (4.5, 4.9)
5.2 (3.2, 7.7)
29.9 (27.9, 32.0)
9.0 (8.1, 9.9)
10.3 (9.8, 10.8)
4.6 (3.2, 6.2)
ES (95% CI)
1.1 (1.0, 1.2)
2.8 (2.5, 3.1)
1.3 (0.2, 4.4)
3.2 (2.1, 4.6)
4.5 (4.1, 4.9)
0.5 (0.2, 1.1)
7.4 (6.5, 8.4)
13.9 (13.6, 14.2)
1.8 (0.4, 5.3)
1.1 (0.9, 1.3)
0.7 (0.0, 3.6)
1.2 (0.3, 2.5)
8.2 (7.8, 8.7)
2.6 (2.4, 2.9)
3.1 (2.7, 3.6)
1.4 (1.2, 1.6)0.9 (0.8, 1.0)
3.5 (3.3, 3.7)
3.9 (3.5, 4.3)
0.0 (0.0, 3.7)
13.0 (11.6, 14.4)
13.4 (12.8, 14.0)10.8 (10.5, 11.1)
10.4 (9.7, 11.2)
1.5 (1.3, 1.8)
1.0 (0.9, 1.1)
1.1 (0.9, 1.3)
1.8 (1.7, 1.9)
29.5 (28.2, 30.9)
4.0 (3.8, 4.2)
0.6 (0.4, 0.8)1.5 (1.2, 1.8)
17.7 (15.7, 19.8)
3.9 (3.6, 4.3)
4.7 (4.5, 4.9)
5.2 (3.2, 7.7)
29.9 (27.9, 32.0)
9.0 (8.1, 9.9)
10.3 (9.8, 10.8)
0 10 20 30 40
Figure 10: Pooled analysis of current e-cigarette use among youth by country (2008-2015)
73 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
1: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.2%
, p =
0.0
)
Moo
re
Ham
ilton
Barn
ett
Reid
SALS
US
Moo
re
Babi
neau
Kris
tjans
son
Gallu
s
Fotio
u
Whi
te
Gallu
s
Auth
or
Gallu
s
UK
(Wal
es)
Cana
da (O
ntar
io)
US
(Flo
rida)
Cana
da
UK
(Sco
tlan
d)
UK
(Wal
es)
Irel
and
Icel
and
Ital
y
Gree
ce
New
Zea
land
Ital
y
Coun
try
Ital
y
2014
2015
2013
Dat
a
2013
2013
-201
4
2014
2014
2015
2015
2014
2014
2013
colle
ctio
n
2014
11-1
6
14-1
8
11-1
8
Age
15-1
9
13-1
5
10-1
1
16-1
7
16-1
9
14-1
5
16-1
9
rang
e
16-1
9
8564
2448
1171
9
3814
0
2950
8
1581
670
2963
141
1076
2544
136
N 139
637
153
492
Out
com
e
5187
2222
8181 270
291 356
7(n)
1
7.0
(5.1
, 9.3
)
7.4
(6.9
, 8.0
)
6.3
(5.3
, 7.3
)
4.2
(3.8
, 4.6
)
13.6
(13.
3, 1
3.9)
7.5
(7.2
, 7.8
)
5.1
(4.1
, 6.3
)
12.1
(9.7
, 14.
8)
9.1
(8.1
, 10.
2)
1.4
(0.2
, 5.0
)
8.5
(6.9
, 10.
3)
14.0
(12.
7, 1
5.4)
5.1
(2.1
, 10.
3)
ES (9
5% C
I)
0.7
(0.0
, 3.9
)
7.0
(5.1
, 9.3
)
7.4
(6.9
, 8.0
)
6.3
(5.3
, 7.3
)
4.2
(3.8
, 4.6
)
13.6
(13.
3, 1
3.9)
7.5
(7.2
, 7.8
)
5.1
(4.1
, 6.3
)
12.1
(9.7
, 14.
8)
9.1
(8.1
, 10.
2)
1.4
(0.2
, 5.0
)
8.5
(6.9
, 10.
3)
14.0
(12.
7, 1
5.4)
5.1
(2.1
, 10.
3)
ES (9
5% C
I)
0.7
(0.0
, 3.9
)
05
1015
20
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
3: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h by
cou
ntry
(200
8-20
15)
Figu
re 1
2: S
ensi
tivity
ana
lysi
s of
eve
r e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.2%
, p =
0.0
)
Ham
ilton
[Can
ada
(Ont
ario
), 20
15]
Sour
ce
Barn
ett [
US
(Flo
rida)
, 201
3]
Kris
tjans
son
[Icel
and,
201
5]
Gallu
s [It
aly,
201
4]
East
woo
d [U
K (E
ngla
nd),
2014
]
Moo
re [U
K (W
ales
), 20
14]
Whi
te [N
ew Z
eala
nd, 2
014]
Fotio
u [G
reec
e, 2
014]
Moo
re [U
K (W
ales
), 20
14]
Reid
[Can
ada,
201
3]
Gallu
s [It
aly,
201
5]
Babi
neau
[Ire
land
, 201
4]
East
woo
d [U
K (E
ngla
nd),
2013
]
Gallu
s [It
aly,
201
3]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
14-1
8
rang
e
11-1
8
16-1
9
11-1
6
Age
14-1
5
10-1
1
15-1
9
16-1
9
16-1
7
16-1
9
13-1
5
153
(n)
492
270
1 83 637
Out
com
e
356
91 815187
281347 2222
2448
part
icip
ants
1171
9
2963
139
1790
8564
Num
ber o
f
2544
1076
1581
3814
0
141
670
1888
136
2950
8
6.4
(4.6
, 8.5
)
6.3
(5.3
, 7.3
)
ES (9
5% C
I)
4.2
(3.8
, 4.6
)
9.1
(8.1
, 10.
2)
0.7
(0.0
, 3.9
)
4.6
(3.7
, 5.7
)
7.4
(6.9
, 8.0
)
14.0
(12.
7, 1
5.4)
8.5
(6.9
, 10.
3)
5.1
(4.1
, 6.3
)
13.6
(13.
3, 1
3.9)
1.4
(0.2
, 5.0
)
12.1
(9.7
, 14.
8)
1.8
(1.3
, 2.5
)
5.1
(2.1
, 10.
3)
7.5
(7.2
, 7.8
)
100.
00
6.99
Wei
ght
7.09
7.01
5.43
6.95
7.08
% 7.00
6.84
6.93
7.11
5.45
6.68
6.96
5.40
7.10
6.4
(4.6
, 8.5
)
6.3
(5.3
, 7.3
)
ES (9
5% C
I)
4.2
(3.8
, 4.6
)
9.1
(8.1
, 10.
2)
0.7
(0.0
, 3.9
)
4.6
(3.7
, 5.7
)
7.4
(6.9
, 8.0
)
14.0
(12.
7, 1
5.4)
8.5
(6.9
, 10.
3)
5.1
(4.1
, 6.3
)
13.6
(13.
3, 1
3.9)
1.4
(0.2
, 5.0
)
12.1
(9.7
, 14.
8)
1.8
(1.3
, 2.5
)
5.1
(2.1
, 10.
3)
7.5
(7.2
, 7.8
)
100.
00
6.99
Wei
ght
7.09
7.01
5.43
6.95
7.08
% 7.00
6.84
6.93
7.11
5.45
6.68
6.96
5.40
7.10
010
2030
4060
80
75 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
3: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h by
cou
ntry
(200
8-20
15)
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.6%
, p =
0.0
);
Subt
otal
(I^
2 =
63.1
%, p
= 0
.1)
Cho
Kris
tjans
son
Fotio
u
Ham
ilton
Moo
re
Ital
y
SALS
US
Whi
te
Gallu
s
Subt
otal
(I^
2 =
86.2
%, p
= 0
.0)
Gree
ce
Icel
and
Goni
ewic
z
Auth
or
Cana
da (O
ntar
io)
Babi
neau
Gallu
s
Pola
nd
UK
Barn
ett
Kore
a
Reid
New
Zea
land
Dut
ra
US
Irel
and
Dut
ra
Moo
re
Cana
da
Gallu
s
Subt
otal
(I^
2 =
99.2
%, p
= 0
.0)
Kore
a
Icel
and
Gree
ce
Cana
da (O
ntar
io)
UK
(Wal
es)
UK
(Sco
tlan
d)
New
Zea
land
Ital
y
Pola
nd
Coun
try
Irel
and
Ital
y
US
(Flo
rida)
Cana
da
US
NYT
SU
S N
YTS
UK
(Wal
es)
Ital
y
2008
Dat
a
2015
2014
2015
2014
2013
-201
4
2014
2013
2010
-201
1
colle
ctio
n
2014
2015
2013
2013
2012
2011
2014
2014
13-1
9
Age
14-1
8
10-1
113
-15
14-1
5
16-1
9
15-2
4
rang
e
16-1
7
16-1
9
11-1
8
15-1
9
11-1
811
-18
11-1
6
16-1
9
3402
2963
1076
2448
1581
2950
8
2544
136
9022
N 670
141
1171
9
3814
0
2166
016
575
8564
139
5Out
com
e
270
91 153
812222
356
7785
(n)
812492
5187
945
292
637
1
5.8
(3.8
, 8.1
)
2.1
(0.3
, 5.1
)
0.1
(0.0
, 0.3
)
9.1
(8.1
, 10.
2)
8.5
(6.9
, 10.
3)
6.3
(5.3
, 7.3
)
5.1
(4.1
, 6.3
)7.
5 (7
.2, 7
.8)
14.0
(12.
7, 1
5.4)
5.1
(2.1
, 10.
3)
6.9
(6.0
, 7.8
)
8.7
(8.1
, 9.3
)
ES (9
5% C
I)
12.1
(9.7
, 14.
8)
1.4
(0.2
, 5.0
)
4.2
(3.8
, 4.6
)
13.6
(13.
3, 1
3.9)
4.4
(4.1
, 4.6
)1.
8 (1
.6, 2
.0)
7.4
(6.9
, 8.0
)
0.7
(0.0
, 3.9
)
3.3
(1.8
, 5.4
)
5.8
(3.8
, 8.1
)
2.1
(0.3
, 5.1
)
0.1
(0.0
, 0.3
)
9.1
(8.1
, 10.
2)
8.5
(6.9
, 10.
3)
6.3
(5.3
, 7.3
)
5.1
(4.1
, 6.3
)7.
5 (7
.2, 7
.8)
14.0
(12.
7, 1
5.4)
5.1
(2.1
, 10.
3)
6.9
(6.0
, 7.8
)
8.7
(8.1
, 9.3
)
ES (9
5% C
I)
12.1
(9.7
, 14.
8)
1.4
(0.2
, 5.0
)
4.2
(3.8
, 4.6
)
13.6
(13.
3, 1
3.9)
4.4
(4.1
, 4.6
)1.
8 (1
.6, 2
.0)
7.4
(6.9
, 8.0
)
0.7
(0.0
, 3.9
)
3.3
(1.8
, 5.4
)
05
1015
20
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
5: S
ensi
tivity
ana
lysi
s of
cur
rent
e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Figu
re 1
4: P
oole
d an
alys
is o
f cur
rent
e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.9%
, p =
0.0
)
Moo
re
Gallu
s
Port
er
Auth
or
Barn
ett
Port
er
Gallu
s
Goni
ewic
z
Fotio
u
SALS
US
Gallu
s
Babi
neau
UK
(Wal
es)
Ital
y
US
(Flo
rida)
Coun
try
US
(Flo
rida)
US
(Flo
rida)
Ital
y
Pola
nd
Gree
ce
UK
(Sco
tlan
d)
Ital
y
Irel
and
2014
2015
2014
Dat
a
colle
ctio
n
2013
2014
2013
2013
-201
4
2014
2013
-201
4
2014
2014
11-1
6
16-1
9
15-1
8
Age
rang
e
11-1
8
11-1
4
16-1
9
15-1
9
13-1
5
16-1
9
16-1
7
8564
141
3006
5
N 1171
9
3592
0
136
1221
1076
2950
8
139
670
54 02074
Out
com
e
(n)
2227
1006
0 159
224 010
2.2
(0.3
, 5.6
)
0.6
(0.5
, 0.8
)
0.0
(0.0
, 2.6
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
19.0
(18.
3, 1
9.7)
2.8
(2.6
, 3.0
)
0.0
(0.0
, 2.7
)
13.0
(11.
2, 1
5.0)
0.2
(0.0
, 0.7
)
0.1
(0.1
, 0.1
)
0.0
(0.0
, 2.6
)
1.5
(0.7
, 2.7
)
2.2
(0.3
, 5.6
)
0.6
(0.5
, 0.8
)
0.0
(0.0
, 2.6
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
19.0
(18.
3, 1
9.7)
2.8
(2.6
, 3.0
)
0.0
(0.0
, 2.7
)
13.0
(11.
2, 1
5.0)
0.2
(0.0
, 0.7
)
0.1
(0.1
, 0.1
)
0.0
(0.0
, 2.6
)
1.5
(0.7
, 2.7
)
010
20
77 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
5: S
ensi
tivity
ana
lysi
s of
cur
rent
e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.6%
, p =
0.0
)
Babi
neau
[Ire
land
, 201
4]
Smok
ing
[UK
(Eng
land
), 20
14]
Gallu
s [It
aly,
201
3]
Port
er [U
S (F
lorid
a), 2
014]
Smok
ing
[UK
(Eng
land
), 20
15]
Fotio
u [G
reec
e, 2
014]
Goni
ewic
z [P
olan
d, 2
013-
2014
]
Barn
ett [
US
(Flo
rida)
, 201
3]
East
woo
d [U
K (E
ngla
nd),
2013
]
Moo
re [U
K (W
ales
), 20
14]
Gallu
s [It
aly,
201
5]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
Sour
ce
Gallu
s [It
aly,
201
4]
Port
er [U
S (F
lorid
a), 2
014]
East
woo
d [U
K (E
ngla
nd),
2014
]
16-1
7
16-2
0
16-1
9
11-1
4
16-2
0
15-1
9
Age
11-1
8
11-1
6
16-1
9
13-1
5
rang
e
16-1
9
15-1
8
10 60 1006
132159
Out
com
e
316
5 54 024(n)
0 2074
26
670
1128
136
3592
0
1040
1076
1221
Num
ber o
f
1171
9
1888
8564
141
2950
8
part
icip
ants
139
3006
5
1790
1.3
(0.4
, 2.8
)
1.5
(0.7
, 2.7
)
0.5
(0.2
, 1.2
)
0.0
(0.0
, 2.7
)
2.8
(2.6
, 3.0
)
1.3
(0.7
, 2.1
)
0.2
(0.0
, 0.7
)
13.0
(11.
2, 1
5.0)
2.7
(2.4
, 3.0
)
0.3
(0.1
, 0.6
)
0.6
(0.5
, 0.8
)
0.0
(0.0
, 2.6
)
0.1
(0.1
, 0.1
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
6.9
(6.6
, 7.2
)
1.5
(1.0
, 2.1
)
100.
00
6.70
6.80
5.88
6.95
6.79
6.79
6.81
% 6.94
6.86
6.93
5.91
6.94
Wei
ght
5.90
6.94
6.86
1.3
(0.4
, 2.8
)
1.5
(0.7
, 2.7
)
0.5
(0.2
, 1.2
)
0.0
(0.0
, 2.7
)
2.8
(2.6
, 3.0
)
1.3
(0.7
, 2.1
)
0.2
(0.0
, 0.7
)
13.0
(11.
2, 1
5.0)
2.7
(2.4
, 3.0
)
0.3
(0.1
, 0.6
)
0.6
(0.5
, 0.8
)
0.0
(0.0
, 2.6
)
0.1
(0.1
, 0.1
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
6.9
(6.6
, 7.2
)
1.5
(1.0
, 2.1
)
100.
00
6.70
6.80
5.88
6.95
6.79
6.79
6.81
% 6.94
6.86
6.93
5.91
6.94
Wei
ght
5.90
6.94
6.86
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
7: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Figu
re 1
6: P
oole
d an
alys
is o
f cur
rent
e-c
igar
ette
use
am
ong
non-
smok
ing
yout
h by
cou
ntry
(201
0-20
15)
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
);
Hun
gary
Goni
ewic
z
Subt
otal
(I^
2 =
0.0%
, p =
1.0
)
US
SALS
US
Gree
ce
Hun
gary
Barn
ett
Ital
yGa
llus
Subt
otal
(I^
2 =
99.9
%, p
= 0
.0)
Subt
otal
(I^
2 =
100.
0%, p
= 0
.0)
Port
er
Kore
a
Gallu
s
Lee
Wan
g
Port
er
UK
Dut
ra
Moo
re
Babi
neau
Fotio
u
Dut
ra
Goni
ewic
z
Irel
and
Subt
otal
(I^
2 =
0.0%
, p =
1.0
)
Port
er
Auth
or
Gallu
s
Chin
a (H
ong
Kong
)
Port
er
Pola
nd
Hun
gary
Pola
nd
UK
(Sco
tlan
d)
US
(Flo
rida)
Ital
y
US
(Flo
rida)
Ital
y
Kore
a
Chin
a (H
ong
Kong
)
US
(Flo
rida)
US
NYT
S
UK
(Wal
es)
Irel
and
Gree
ce
US
NYT
S
Pola
nd
US
(Flo
rida)
Coun
try
Ital
y
US
(Flo
rida)
2012
2013
-201
4
2013
-201
4
2013
Dat
a
2013
2011
2014
2011
2012
-201
3
2014
2011
2014
2014
2014
2012
2010
-201
1
2014
colle
ctio
n
2015
2011
13-1
5
15-1
9
13-1
5
11-1
8
Age
16-1
9
11-1
4
16-1
9
13-1
8
12-1
8
11-1
4
11-1
8
11-1
6
16-1
7
11-1
8
15-2
4
15-1
8
rang
e
16-1
9
15-1
8
1697
1221
2950
8
1171
9
136
5791
139
6498
3
4017
9
3592
0
1657
5
8564
670
1076
2166
0
9022
3006
5
N 141
5362
80159
242227
Out
com
e
041 03698
221
1006
98 54 102232
217
2074
(n)
043
2.0
(0.8
, 3.7
)
4.7
(3.8
, 5.8
)
13.0
(11.
2, 1
5.0)
0.2
(0.1
, 0.2
)
0.1
(0.1
, 0.1
)
19.0
(18.
3, 1
9.7)
0.0
(0.0
, 2.7
)
3.1
(0.8
, 6.9
)
3.2
(2.9
, 3.6
)
0.7
(0.5
, 1.0
)
0.0
(0.0
, 2.6
)
5.7
(5.5
, 5.9
)
0.6
(0.5
, 0.6
)
2.8
(2.6
, 3.0
)
0.6
(0.5
, 0.7
)
0.6
(0.5
, 0.8
)
1.5
(0.7
, 2.7
)
0.2
(0.0
, 0.7
)
1.1
(0.9
, 1.2
)
2.4
(2.1
, 2.7
)
0.0
(0.0
, 0.5
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
0.8
(0.6
, 1.1
)
2.0
(0.8
, 3.7
)
4.7
(3.8
, 5.8
)
13.0
(11.
2, 1
5.0)
0.2
(0.1
, 0.2
)
0.1
(0.1
, 0.1
)
19.0
(18.
3, 1
9.7)
0.0
(0.0
, 2.7
)
3.1
(0.8
, 6.9
)
3.2
(2.9
, 3.6
)
0.7
(0.5
, 1.0
)
0.0
(0.0
, 2.6
)
5.7
(5.5
, 5.9
)
0.6
(0.5
, 0.6
)
2.8
(2.6
, 3.0
)
0.6
(0.5
, 0.7
)
0.6
(0.5
, 0.8
)
1.5
(0.7
, 2.7
)
0.2
(0.0
, 0.7
)
1.1
(0.9
, 1.2
)
2.4
(2.1
, 2.7
)
0.0
(0.0
, 0.5
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
0.8
(0.6
, 1.1
)
010
20
79 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
7: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.8%
, p =
0.0
);
Hun
gary
Goni
ewic
z
Subt
otal
(I^
2 =
0.0%
, p =
1.0
)
US
SALS
US
Gree
ce
Hun
gary
Barn
ett
Ital
yGa
llus
Subt
otal
(I^
2 =
99.9
%, p
= 0
.0)
Subt
otal
(I^
2 =
100.
0%, p
= 0
.0)
Port
er
Kore
a
Gallu
s
Lee
Wan
g
Port
er
UK
Dut
ra
Moo
re
Babi
neau
Fotio
u
Dut
ra
Goni
ewic
z
Irel
and
Subt
otal
(I^
2 =
0.0%
, p =
1.0
)
Port
er
Auth
or
Gallu
s
Chin
a (H
ong
Kong
)
Port
er
Pola
nd
Hun
gary
Pola
nd
UK
(Sco
tlan
d)
US
(Flo
rida)
Ital
y
US
(Flo
rida)
Ital
y
Kore
a
Chin
a (H
ong
Kong
)
US
(Flo
rida)
US
NYT
S
UK
(Wal
es)
Irel
and
Gree
ce
US
NYT
S
Pola
nd
US
(Flo
rida)
Coun
try
Ital
y
US
(Flo
rida)
2012
2013
-201
4
2013
-201
4
2013
Dat
a
2013
2011
2014
2011
2012
-201
3
2014
2011
2014
2014
2014
2012
2010
-201
1
2014
colle
ctio
n
2015
2011
13-1
5
15-1
9
13-1
5
11-1
8
Age
16-1
9
11-1
4
16-1
9
13-1
8
12-1
8
11-1
4
11-1
8
11-1
6
16-1
7
11-1
8
15-2
4
15-1
8
rang
e
16-1
9
15-1
8
1697
1221
2950
8
1171
9
136
5791
139
6498
3
4017
9
3592
0
1657
5
8564
670
1076
2166
0
9022
3006
5
N 141
5362
80159
242227
Out
com
e
041 03698
221
1006
98 54 102232
217
2074
(n)
043
2.0
(0.8
, 3.7
)
4.7
(3.8
, 5.8
)
13.0
(11.
2, 1
5.0)
0.2
(0.1
, 0.2
)
0.1
(0.1
, 0.1
)
19.0
(18.
3, 1
9.7)
0.0
(0.0
, 2.7
)
3.1
(0.8
, 6.9
)
3.2
(2.9
, 3.6
)
0.7
(0.5
, 1.0
)
0.0
(0.0
, 2.6
)
5.7
(5.5
, 5.9
)
0.6
(0.5
, 0.6
)
2.8
(2.6
, 3.0
)
0.6
(0.5
, 0.7
)
0.6
(0.5
, 0.8
)
1.5
(0.7
, 2.7
)
0.2
(0.0
, 0.7
)
1.1
(0.9
, 1.2
)
2.4
(2.1
, 2.7
)
0.0
(0.0
, 0.5
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
0.8
(0.6
, 1.1
)
2.0
(0.8
, 3.7
)
4.7
(3.8
, 5.8
)
13.0
(11.
2, 1
5.0)
0.2
(0.1
, 0.2
)
0.1
(0.1
, 0.1
)
19.0
(18.
3, 1
9.7)
0.0
(0.0
, 2.7
)
3.1
(0.8
, 6.9
)
3.2
(2.9
, 3.6
)
0.7
(0.5
, 1.0
)
0.0
(0.0
, 2.6
)
5.7
(5.5
, 5.9
)
0.6
(0.5
, 0.6
)
2.8
(2.6
, 3.0
)
0.6
(0.5
, 0.7
)
0.6
(0.5
, 0.8
)
1.5
(0.7
, 2.7
)
0.2
(0.0
, 0.7
)
1.1
(0.9
, 1.2
)
2.4
(2.1
, 2.7
)
0.0
(0.0
, 0.5
)
6.9
(6.6
, 7.2
)
ES (9
5% C
I)
0.0
(0.0
, 2.6
)
0.8
(0.6
, 1.1
)
010
20
Ove
rall
(I^2
= 9
7.9%
, p =
0.0
)
Gallu
s
Kris
tjans
son
Gallu
s
Moo
re
Ham
ilton
Auth
or
Whi
te
Fotio
u
Gallu
s
Babi
neau
Reid
Barn
ett
Moo
re
SALS
US
Ital
y
Icel
and
Ital
y
UK
(Wal
es)
Cana
da (O
ntar
io)
Coun
try
New
Zea
land
Gree
ce
Ital
y
Irel
and
Cana
da
US
(Flo
rida)
UK
(Wal
es)
UK
(Sco
tlan
d)
2015
2015
2014
2014
2015
colle
ctio
n
2014
2014
2013
2014
2013
2013
2014
2013
-201
4
Dat
a
16-1
9
16-1
9
11-1
6
14-1
8
rang
e
14-1
5
16-1
9
16-1
7
15-1
9
11-1
8
10-1
1
13-1
5
Age
19514
14 465
442
N 375
244
27 151
9063
896
122543
5317
5 246
253
(n)
228
128
8 896571
603
61265
Out
com
e
54.7
(47.
0, 6
2.3)
26.3
(9.1
, 51.
2)
61.7
(57.
3, 6
5.9)
35.7
(12.
8, 6
4.9)
52.9
(48.
3, 5
7.5)
57.2
(52.
5, 6
1.9)
ES (9
5% C
I)
60.8
(55.
7, 6
5.8)
52.5
(46.
0, 5
8.9)
29.6
(13.
8, 5
0.2)
58.9
(50.
7, 6
6.9)
72.5
(71.
6, 7
3.4)
67.3
(64.
1, 7
0.4)
50.0
(21.
1, 7
8.9)
49.7
(47.
8, 5
1.7)
54.7
(47.
0, 6
2.3)
26.3
(9.1
, 51.
2)
61.7
(57.
3, 6
5.9)
35.7
(12.
8, 6
4.9)
52.9
(48.
3, 5
7.5)
57.2
(52.
5, 6
1.9)
ES (9
5% C
I)
60.8
(55.
7, 6
5.8)
52.5
(46.
0, 5
8.9)
29.6
(13.
8, 5
0.2)
58.9
(50.
7, 6
6.9)
72.5
(71.
6, 7
3.4)
67.3
(64.
1, 7
0.4)
50.0
(21.
1, 7
8.9)
49.7
(47.
8, 5
1.7)
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
9: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
smok
ing
yout
h by
cou
ntry
(200
8-20
15)
Figu
re 1
8: S
ensi
tivity
ana
lysi
s of
eve
r e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
7.8%
, p =
0.0
)
Sour
ce
Kris
tjans
son
[Icel
and,
201
5]
Gallu
s [It
aly,
201
3]
Moo
re [U
K (W
ales
), 20
14]
Fotio
u [G
reec
e, 2
014]
Gallu
s [It
aly,
201
4]
Moo
re [U
K (W
ales
), 20
14]
Ham
ilton
[Can
ada
(Ont
ario
), 20
15]
East
woo
d [U
K (E
ngla
nd),
2014
]
East
woo
d [U
K (E
ngla
nd),
2013
]
Babi
neau
[Ire
land
, 201
4]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
Gallu
s [It
aly,
201
5]
Whi
te [N
ew Z
eala
nd, 2
014]
Barn
ett [
US
(Flo
rida)
, 201
3]
Reid
[Can
ada,
201
3]
rang
e
16-1
9
11-1
6
16-1
9
10-1
1
14-1
8
16-1
7
13-1
5
16-1
9
14-1
5
11-1
8
15-1
9
Age
(n)
317
8 246
128
5 6 253
7357 891265
5228
603
6571
Out
com
e
part
icip
ants
514
27 465
244
14 12 442
136
156
151
2543
19375
896
9063
Num
ber o
f
53.2
(45.
9, 6
0.5)
ES (9
5% C
I)
61.7
(57.
3, 6
5.9)
29.6
(13.
8, 5
0.2)
52.9
(48.
3, 5
7.5)
52.5
(46.
0, 5
8.9)
35.7
(12.
8, 6
4.9)
50.0
(21.
1, 7
8.9)
57.2
(52.
5, 6
1.9)
53.7
(44.
9, 6
2.3)
36.5
(29.
0, 4
4.6)
58.9
(50.
7, 6
6.9)
49.7
(47.
8, 5
1.7)
26.3
(9.1
, 51.
2)
60.8
(55.
7, 6
5.8)
67.3
(64.
1, 7
0.4)
72.5
(71.
6, 7
3.4)
100.
00
Wei
ght
7.65
5.14
7.63
7.43
3.92
3.63
7.62
7.11
7.20
7.18
7.82
4.50
7.57
7.74
7.86
%
53.2
(45.
9, 6
0.5)
ES (9
5% C
I)
61.7
(57.
3, 6
5.9)
29.6
(13.
8, 5
0.2)
52.9
(48.
3, 5
7.5)
52.5
(46.
0, 5
8.9)
35.7
(12.
8, 6
4.9)
50.0
(21.
1, 7
8.9)
57.2
(52.
5, 6
1.9)
53.7
(44.
9, 6
2.3)
36.5
(29.
0, 4
4.6)
58.9
(50.
7, 6
6.9)
49.7
(47.
8, 5
1.7)
26.3
(9.1
, 51.
2)
60.8
(55.
7, 6
5.8)
67.3
(64.
1, 7
0.4)
72.5
(71.
6, 7
3.4)
100.
00
Wei
ght
7.65
5.14
7.63
7.43
3.92
3.63
7.62
7.11
7.20
7.18
7.82
4.50
7.57
7.74
7.86
%
010
2030
4060
80
81 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 1
9: P
oole
d an
alys
is o
f eve
r e-c
igar
ette
use
am
ong
smok
ing
yout
h by
cou
ntry
(200
8-20
15)
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.5%
, p =
0.0
);
Moo
re
Kore
a
SALS
US
Cana
da
US
Subt
otal
(I^
2 =
0.0%
, p =
0.8
)
New
Zea
land
Moo
re
Icel
and
Whi
te
Barn
ett
Ital
yGa
llus
Fotio
u
Auth
or
Gree
ce
Gallu
sGa
llus
Dut
ra
Pola
nd
Irel
and
Babi
neau
Reid
Subt
otal
(I^
2 =
99.3
%, p
= 0
.0)
Cho
Ham
ilton
Subt
otal
(I^
2 =
0.0%
, p =
0.5
)
Goni
ewic
z
Kris
tjans
son
UK
Dut
ra
Cana
da (O
ntar
io)
UK
(Wal
es)
UK
(Sco
tlan
d)
UK
(Wal
es)
New
Zea
land
US
(Flo
rida)
Ital
y
Gree
ce
Coun
try
Ital
yIt
aly
US
NYT
S
Irel
and
Cana
da
Kore
a
Cana
da (O
ntar
io)
Pola
nd
Icel
and
US
NYT
S
2014
2013
-201
4
2014
2014
Dat
a
2013
2013
2014
colle
ctio
n
2015
2014
2011
2014
2013
2008
2015
2010
-201
1
2015
2012
10-1
113
-15
11-1
6
14-1
5
Age
11-1
8
16-1
9
rang
e
16-1
916
-19
11-1
8
16-1
7
15-1
9
13-1
9
14-1
8
15-2
4
11-1
8
122543
465
375
896
27 244
N 1914778
151
9063
810
442
4738
514
869
61265
246
228
Out
com
e
603
8 128
(n)
55219
896571
16 253
2042
317
505
47.0
(36.
0, 5
8.1)
50.0
(21.
1, 7
8.9)
49.7
(47.
8, 5
1.7)
29.9
(18.
5, 4
2.5)
52.9
(48.
3, 5
7.5)
60.8
(55.
7, 6
5.8)
67.3
(64.
1, 7
0.4)
29.6
(13.
8, 5
0.2)
52.5
(46.
0, 5
8.9)
ES (9
5% C
I)
26.3
(9.1
, 51.
2)35
.7 (1
2.8,
64.
9)
28.1
(25.
0, 3
1.5)
58.9
(50.
7, 6
6.9)
72.5
(71.
6, 7
3.4)
51.1
(28.
4, 7
3.5)
2.0
(1.1
, 3.2
)
57.2
(52.
5, 6
1.9)
50.2
(48.
4, 5
2.1)
43.1
(41.
7, 4
4.5)
61.7
(57.
3, 6
5.9)
58.1
(54.
8, 6
1.4)
47.0
(36.
0, 5
8.1)
50.0
(21.
1, 7
8.9)
49.7
(47.
8, 5
1.7)
29.9
(18.
5, 4
2.5)
52.9
(48.
3, 5
7.5)
60.8
(55.
7, 6
5.8)
67.3
(64.
1, 7
0.4)
29.6
(13.
8, 5
0.2)
52.5
(46.
0, 5
8.9)
ES (9
5% C
I)
26.3
(9.1
, 51.
2)35
.7 (1
2.8,
64.
9)
28.1
(25.
0, 3
1.5)
58.9
(50.
7, 6
6.9)
72.5
(71.
6, 7
3.4)
51.1
(28.
4, 7
3.5)
2.0
(1.1
, 3.2
)
57.2
(52.
5, 6
1.9)
50.2
(48.
4, 5
2.1)
43.1
(41.
7, 4
4.5)
61.7
(57.
3, 6
5.9)
58.1
(54.
8, 6
1.4)
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 2
1: P
oole
d an
alys
is o
f cur
rent
e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Figu
re 2
0: P
oole
d an
alys
is o
f cur
rent
e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.6%
, p =
0.0
)
SALS
US
Babi
neau
Gallu
s
Goni
ewic
z
Port
er
Moo
re
Port
er
Gallu
s
Fotio
u
Auth
or
Gallu
s
Barn
ett
UK
(Sco
tlan
d)
Irel
and
Ital
y
Pola
nd
US
(Flo
rida)
UK
(Wal
es)
US
(Flo
rida)
Ital
y
Gree
ce
Coun
try
Ital
y
US
(Flo
rida)
2013
-201
4
2014
2013
2013
-201
4
2014
2014
2014
2014
2014
colle
ctio
n
2015
2013
Dat
a
13-1
5
16-1
7
16-1
9
15-1
9
11-1
4
11-1
6
15-1
8
16-1
9
rang
e
16-1
9
11-1
8
Age
2543
151
27 749
1073
465
2865
14244
N 19896
252
163 430
481
71 1481
15(n)
124Out
com
e
17.2
(5.8
, 32.
6)
9.9
(8.8
, 11.
1)
10.6
(6.2
, 16.
6)
11.1
(2.4
, 29.
2)
57.4
(53.
8, 6
1.0)
44.8
(41.
8, 4
7.9)
15.3
(12.
1, 1
8.9)
51.7
(49.
8, 5
3.5)
7.1
(0.2
, 33.
9)
2.0
(0.7
, 4.7
)
ES (9
5% C
I)
5.3
(0.1
, 26.
0)
2.7
(1.7
, 4.0
)
17.2
(5.8
, 32.
6)
9.9
(8.8
, 11.
1)
10.6
(6.2
, 16.
6)
11.1
(2.4
, 29.
2)
57.4
(53.
8, 6
1.0)
44.8
(41.
8, 4
7.9)
15.3
(12.
1, 1
8.9)
51.7
(49.
8, 5
3.5)
7.1
(0.2
, 33.
9)
2.0
(0.7
, 4.7
)
ES (9
5% C
I)
5.3
(0.1
, 26.
0)
2.7
(1.7
, 4.0
)
010
2030
4060
80
83 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 2
1: P
oole
d an
alys
is o
f cur
rent
e-c
igar
ette
use
am
ong
smok
ing
yout
h fr
om 2
013-
2015
Ove
rall
(I^2
= 9
9.3%
, p =
0.0
)
Fotio
u [G
reec
e, 2
014]
Port
er [U
S (F
lorid
a), 2
014]
Smok
ing
[UK
(Eng
land
), 20
14]
Gallu
s [It
aly,
201
3]
Gallu
s [It
aly,
201
4]
Moo
re [U
K (W
ales
), 20
14]
SALS
US
[UK
(Sco
tlan
d), 2
013-
2014
]
East
woo
d [U
K (E
ngla
nd),
2014
]
Goni
ewic
z [P
olan
d, 2
013-
2014
]
Babi
neau
[Ire
land
, 201
4]
Sour
ce
Barn
ett [
US
(Flo
rida)
, 201
3]
Port
er [U
S (F
lorid
a), 2
014]
Smok
ing
[UK
(Eng
land
), 20
15]
East
woo
d [U
K (E
ngla
nd),
2013
]
Gallu
s [It
aly,
201
5]
11-1
4
16-2
0
16-1
9
16-1
9
11-1
6
13-1
5
15-1
9
16-1
7
rang
e
11-1
8
15-1
8
16-2
0
16-1
9
Age
5 481
433 1 71252
18430
16(n)
170
1481
5612 1Out
com
e
244
1073
277
27 14 465
2543
136
749
151
part
icip
ants
896
2865
292
156
19Num
ber o
f
17.8
(8.8
, 28.
9)
2.0
(0.7
, 4.7
)
44.8
(41.
8, 4
7.9)
15.5
(11.
5, 2
0.3)
11.1
(2.4
, 29.
2)
7.1
(0.2
, 33.
9)
15.3
(12.
1, 1
8.9)
9.9
(8.8
, 11.
1)
13.2
(8.0
, 20.
1)
57.4
(53.
8, 6
1.0)
10.6
(6.2
, 16.
6)
ES (9
5% C
I)
19.0
(16.
5, 2
1.7)
51.7
(49.
8, 5
3.5)
19.2
(14.
8, 2
4.2)
7.7
(4.0
, 13.
1)
5.3
(0.1
, 26.
0)
100.
00
6.86
6.95
6.87
6.09
5.47
6.91
6.96
6.78
6.94
6.79
Wei
ght
6.94
6.96
6.88
6.80
5.79
%
17.8
(8.8
, 28.
9)
2.0
(0.7
, 4.7
)
44.8
(41.
8, 4
7.9)
15.5
(11.
5, 2
0.3)
11.1
(2.4
, 29.
2)
7.1
(0.2
, 33.
9)
15.3
(12.
1, 1
8.9)
9.9
(8.8
, 11.
1)
13.2
(8.0
, 20.
1)
57.4
(53.
8, 6
1.0)
10.6
(6.2
, 16.
6)
ES (9
5% C
I)
19.0
(16.
5, 2
1.7)
51.7
(49.
8, 5
3.5)
19.2
(14.
8, 2
4.2)
7.7
(4.0
, 13.
1)
5.3
(0.1
, 26.
0)
100.
00
6.86
6.95
6.87
6.09
5.47
6.91
6.96
6.78
6.94
6.79
Wei
ght
6.94
6.96
6.88
6.80
5.79
%
010
2030
4060
80
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 2
3: P
oole
d ad
just
ed o
dds
ratio
for l
ongi
tudi
nal s
tudi
es a
sses
sing
ass
ocia
tion
of e
ver e
-cig
aret
te
use
amon
g no
n-sm
oker
s at
bas
elin
e w
ith to
bacc
o ci
gare
tte
upta
ke
Figu
re 2
2: P
oole
d an
alys
es o
f cur
rent
e-c
igar
ette
use
am
ong
smok
ing
yout
h by
cou
ntry
(201
0-20
15)
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.7%
, p =
0.0
);
Gallu
s
Subt
otal
(I^
2 =
0.0%
, p =
0.6
)
Auth
or
Gallu
s
Kore
a
US
Barn
ett
Port
er
Irel
and
Pola
nd
Babi
neau
Goni
ewic
z
Gallu
s
SALS
US
Wan
g
Ital
y
Port
er
Goni
ewic
z
Port
er
Dut
ra
Gree
ce
Lee
Moo
re
Port
er
Subt
otal
(I^
2 =
0.0%
, p =
0.8
)
Chin
a (H
ong
Kong
)
Subt
otal
(I^
2 =
100.
0%, p
= 0
.0)
Subt
otal
(I^
2 =
99.6
%, p
= 0
.0)
Dut
ra
Fotio
u
UK
Ital
y
Coun
try
Ital
y
US
(Flo
rida)
US
(Flo
rida)
Irel
and
Pola
nd
Ital
y
UK
(Sco
tlan
d)
Chin
a (H
ong
Kong
)
US
(Flo
rida)
Pola
nd
US
(Flo
rida)
US
NYT
S
Kore
a
UK
(Wal
es)
US
(Flo
rida)
US
NYT
S
Gree
ce
2015
colle
ctio
n
2014
2013
Dat
a
2014
2014
2010
-201
1
2013
2013
-201
4
2012
-201
3
2011
2013
-201
4
2014
2012
2011
2014
2011
2011
2014
16-1
9
rang
e
16-1
9
11-1
8
Age
11-1
4
16-1
7
15-2
4
16-1
9
13-1
5
12-1
8
15-1
8
15-1
9
15-1
8
11-1
8
13-1
8
11-1
6
11-1
4
11-1
8
19N 14896
1073
151
4738
27 2543
4978
801
749
2865
869
7302
465
254
778
244
1(n)
124Out
com
e
481
16725
3 252
218
147
430
1481
230
2672
7148 76 5
17.4
(9.9
, 26.
4)
5.3
(0.1
, 26.
0)
10.6
(9.6
, 11.
8)
ES (9
5% C
I)
7.1
(0.2
, 33.
9)
2.7
(1.7
, 4.0
)44
.8 (4
1.8,
47.
9)
10.6
(6.2
, 16.
6)
15.3
(14.
3, 1
6.4)
11.1
(2.4
, 29.
2)
9.9
(8.8
, 11.
1)
4.4
(3.8
, 5.0
)
18.4
(15.
7, 2
1.2)
57.4
(53.
8, 6
1.0)
51.7
(49.
8, 5
3.5)
26.5
(23.
6, 2
9.5)
36.6
(35.
5, 3
7.7)
15.3
(12.
1, 1
8.9)
18.9
(14.
3, 2
4.3)
8.1
(1.8
, 17.
1)
20.0
(19.
0, 2
1.1)
22.4
(8.8
, 40.
0)
9.8
(7.8
, 12.
1)
2.0
(0.7
, 4.7
)
17.4
(9.9
, 26.
4)
5.3
(0.1
, 26.
0)
10.6
(9.6
, 11.
8)
ES (9
5% C
I)
7.1
(0.2
, 33.
9)
2.7
(1.7
, 4.0
)44
.8 (4
1.8,
47.
9)
10.6
(6.2
, 16.
6)
15.3
(14.
3, 1
6.4)
11.1
(2.4
, 29.
2)
9.9
(8.8
, 11.
1)
4.4
(3.8
, 5.0
)
18.4
(15.
7, 2
1.2)
57.4
(53.
8, 6
1.0)
51.7
(49.
8, 5
3.5)
26.5
(23.
6, 2
9.5)
36.6
(35.
5, 3
7.7)
15.3
(12.
1, 1
8.9)
18.9
(14.
3, 2
4.3)
8.1
(1.8
, 17.
1)
20.0
(19.
0, 2
1.1)
22.4
(8.8
, 40.
0)
9.8
(7.8
, 12.
1)
2.0
(0.7
, 4.7
)
010
2030
4060
80
85 Prevalence of smoking-proxy electronic inhaling system (SEIS) use and its association with tobacco initiation in youths: a systematic review
This report was prepared at the request of WHO Prevention of Noncommunicable Diseases. The findings, interpretations, and conclusions expressed in this work do not necessarily reflect the views of WHO.
Figu
re 2
3: P
oole
d ad
just
ed o
dds
ratio
for l
ongi
tudi
nal s
tudi
es a
sses
sing
ass
ocia
tion
of e
ver e
-cig
aret
te
use
amon
g no
n-sm
oker
s at
bas
elin
e w
ith to
bacc
o ci
gare
tte
upta
ke
Het
erog
enei
ty b
etw
een
grou
ps: p
= 0
.000
Ove
rall
(I^2
= 9
9.7%
, p =
0.0
);
Gallu
s
Subt
otal
(I^
2 =
0.0%
, p =
0.6
)
Auth
or
Gallu
s
Kore
a
US
Barn
ett
Port
er
Irel
and
Pola
nd
Babi
neau
Goni
ewic
z
Gallu
s
SALS
US
Wan
g
Ital
y
Port
er
Goni
ewic
z
Port
er
Dut
ra
Gree
ce
Lee
Moo
re
Port
er
Subt
otal
(I^
2 =
0.0%
, p =
0.8
)
Chin
a (H
ong
Kong
)
Subt
otal
(I^
2 =
100.
0%, p
= 0
.0)
Subt
otal
(I^
2 =
99.6
%, p
= 0
.0)
Dut
ra
Fotio
u
UK
Ital
y
Coun
try
Ital
y
US
(Flo
rida)
US
(Flo
rida)
Irel
and
Pola
nd
Ital
y
UK
(Sco
tlan
d)
Chin
a (H
ong
Kong
)
US
(Flo
rida)
Pola
nd
US
(Flo
rida)
US
NYT
S
Kore
a
UK
(Wal
es)
US
(Flo
rida)
US
NYT
S
Gree
ce
2015
colle
ctio
n
2014
2013
Dat
a
2014
2014
2010
-201
1
2013
2013
-201
4
2012
-201
3
2011
2013
-201
4
2014
2012
2011
2014
2011
2011
2014
16-1
9
rang
e
16-1
9
11-1
8
Age
11-1
4
16-1
7
15-2
4
16-1
9
13-1
5
12-1
8
15-1
8
15-1
9
15-1
8
11-1
8
13-1
8
11-1
6
11-1
4
11-1
8
19N 14896
1073
151
4738
27 2543
4978
801
749
2865
869
7302
465
254
778
244
1(n)
124Out
com
e
481
16725
3 252
218
147
430
1481
230
2672
7148 76 5
17.4
(9.9
, 26.
4)
5.3
(0.1
, 26.
0)
10.6
(9.6
, 11.
8)
ES (9
5% C
I)
7.1
(0.2
, 33.
9)
2.7
(1.7
, 4.0
)44
.8 (4
1.8,
47.
9)
10.6
(6.2
, 16.
6)
15.3
(14.
3, 1
6.4)
11.1
(2.4
, 29.
2)
9.9
(8.8
, 11.
1)
4.4
(3.8
, 5.0
)
18.4
(15.
7, 2
1.2)
57.4
(53.
8, 6
1.0)
51.7
(49.
8, 5
3.5)
26.5
(23.
6, 2
9.5)
36.6
(35.
5, 3
7.7)
15.3
(12.
1, 1
8.9)
18.9
(14.
3, 2
4.3)
8.1
(1.8
, 17.
1)
20.0
(19.
0, 2
1.1)
22.4
(8.8
, 40.
0)
9.8
(7.8
, 12.
1)
2.0
(0.7
, 4.7
)
17.4
(9.9
, 26.
4)
5.3
(0.1
, 26.
0)
10.6
(9.6
, 11.
8)
ES (9
5% C
I)
7.1
(0.2
, 33.
9)
2.7
(1.7
, 4.0
)44
.8 (4
1.8,
47.
9)
10.6
(6.2
, 16.
6)
15.3
(14.
3, 1
6.4)
11.1
(2.4
, 29.
2)
9.9
(8.8
, 11.
1)
4.4
(3.8
, 5.0
)
18.4
(15.
7, 2
1.2)
57.4
(53.
8, 6
1.0)
51.7
(49.
8, 5
3.5)
26.5
(23.
6, 2
9.5)
36.6
(35.
5, 3
7.7)
15.3
(12.
1, 1
8.9)
18.9
(14.
3, 2
4.3)
8.1
(1.8
, 17.
1)
20.0
(19.
0, 2
1.1)
22.4
(8.8
, 40.
0)
9.8
(7.8
, 12.
1)
2.0
(0.7
, 4.7
)
010
2030
4060
80
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