Dr. Erika Avila Tang

Department of Epidemiology

Institute for Global Tobacco Control

How do we Measure Secondhand Smoke Exposure?

FAMRI Expert SHSe Assessment

Goal:

To catalogue the approaches for Secondhand Smoke exposure (SHSe) assessment

Provide a set of uniform methods for future use to facilitate comparisons of findings across studies

Comprehensive topic assessments on:

Questionnaires and self-reported methods

Biological samples

Environmental samples

Flight Attendant Medical Research Institute (FAMRI) Centers of Excellence

American Academy of Pediatrics Julius B. Richmond, Illinois, USA

Johns Hopkins University, Maryland, USA

University of California, San Francisco Bland Lane, California, USA

More than 20 researchers on SHSe assessment involved

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Why would we want to measure SHSe?

SHSe is a key element of tobacco control

research and implementation worldwide

To estimate the SHSe overall burden of disease

To determine the risks associated with SHSe

To assess population trends in support of and

evaluate tobacco control policies

To support and evaluate behavioral interventions

Topic assessments

Questionnaires and self-reported methods

Biological samples

Environmental samples

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Self-reported methods of assessment

Questionnaires

Most commonly used

Inexpensive and feasible for large studies

Assessment of :

Current and long-term exposure

Time-activity patterns

Recall can be an issue

Diaries

Recall burden is reduced but respondent’s burden is increased

E.g. Report over the past day vs. past week/month

Higher awareness of instances of exposure

Accuracy: validity and reliability

Review of studies assessing the validity and/or

reliability of questions

Validation of questions against a “gold

standard”:

Air measurement

Biomarker

Reliability=repeatability

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Conclusions for questionnaires and self-

reported methods

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Reliable responses for SHSe in their lifetime, childhood, and current among adults.

For children, CPD from parents, in their presence, and in places

Research on testing the accuracy of questions are still needed

Current exposure for adults and children, including intensity and duration of exposure

Exposure at home, in transport, and in social settings

Collaboration of FAMRI CoEs: AAP Richmond, Johns Hopkins, and UCSF Bland Lane are testing questions in pilot studies to continue building a set of core questions

Topic assessments

Questionnaires and self-reported methods

Biological samples

Environmental samples

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Biomarkers

Tobacco-specific biomarkers

Cotinine

Reflects recent SHSe (t1/2 16 hours (average))

Nicotine/cotinine in hair or toenails

Reflects “longer exposure”: 1 cm of hair proximal to the

scalp ≈ last month’s exposure; 1 mm ≈ last month’s

exposure

NNAL (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanol)

Reflects “longer exposure” (t1/2 up to 3 weeks)

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Biomarker- Cotinine

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Matrix Cut-off Pros Cons

Urine Non-invasive

50 ng/ml for higher SHSe

Higher concentrations than other matrices (higher sensitivity)

Need of facilities with privacy during collection

Difficulty for population-based or children studies

Need for creatinine clearance adjustment

Collect data on renal disease and some prescription drugs

Blood Invasive

12 ng/ml for higher SHSe

3 ng/ml for lower

SHSe

No adjustment required for hydration

Pregnant women have increased clearance rate

Difficulty for infants and young children

Lower sensitivity

Saliva Non-invasive

14 ng/ml for higher SHSe

Good for multiple measurements over a limited period of time

Potential issues with age, gender, race, oral pH, type of diet, dehydration, or drug treatment

Lower sensitivity

Biomarker- Nicotine/Cotinine

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Matrix Cut-off Pros Cons

Hair Non-invasive

0.8 ng/mg (Women)

0.2 ng/mg (Pregnant)

0.2 ng/mg (Children)

Easy to collect, ship, and store (room temperature ≤ 5 years)

Less affected by daily variability (fluctuating exposure, varying metabolism, and nicotine elimination)

Represents longer exposure

Scarcity of hair in infants and adults

Chemical hair treatments can reduce concentrations by 9%-30%

Age, gender, and race may play roles in determining hair nicotine concentrations

Toenails Non-invasive

Not available

Easy to collect, ship, and store (room temperature ≤ 20 years)

Overcomes day-to-day exposure variability

Represents longer exposure

Need for further research and population concentrations

Biomarker- NNAL

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Matrix Cut-off Pros Cons

Urine Not available

Related to a lung carcinogen

Represents longer exposure than cotinine (urine/blood/saliva)

Analytical expertise

Costly equipment

NNAL is carcinogenic and mutagenic, special lab handling

Further research needed

Topic assessments

Questionnaires and self-reported methods

Biological samples

Environmental samples

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Environmental measurements

Most widely used methods:

Nicotine: passive air monitor

Particulate matter (< 2.5µ (PM2.5)) monitor

Correlation between nicotine and PM when

measured in the same setting using a common

sampling period

An increase in 1 µg/m3 of nicotine concentration ≈ an

average increase of 10 µg/m3 of PM

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Air nicotine monitoring

Highly specific to tobacco smoke

Monitors (1-3) placed in each venue (hung from the

ceiling) for 5 to14 days

Filters are soaked in a bi-sodium sulfate solution that

captures nicotine on the filter

No expensive equipment to buy

up front and minimal operating

cost but requires lab analysis

Per sample laboratory costs

including the filter badge are

~$40-$100 USD

Particulate matter monitoring

Active, real-time monitor

Uses light scattering to measure particulate

matter concentrations (e.g. PM2.5)

Air quality standards makes easier

dissemination

Other causes of indoor air particles

High initial investment

~3,000 USD

Minimal operating cost

No per sample costs

Potential costs in labor for data analysis

Overall findings

Questionnaires are the most effective way to know if people are exposed – but not how much they are exposed

Research on testing the accuracy of questions are still needed

Choice of any SHSe assessment method depends on your needs

Study’s objectives, subjects, design and setting and funding

Selection of a biomarker will dependent on:

Issues of privacy, invasiveness, and subject’s age

The length of SHSe may result in selecting hair or toenails over bio-fluids

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Acknowledgements

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Melbourne Hovell

Andrew Hyland

Sungroul Kim

Jonathan Klein

Neil Klepeis

Robert McMillen

James Repace

Jonathan Samet

Jonathan Winickoff

Ana Navas-Acien

Lisa Hepp

Jessica Elf

Camille Madsen

Wael Al-Delaimy

Benjamin Apelberg

David Ashley

Erika Avila-Tang

Neil Benowitz

Thomas Bernert

Dana Best

Patrick Breysse

Michael Cummings

Geoffrey Fong

Lara Gundel

Kathie Hammond

Stephen Hecht