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Journal of Ethnopharmacology 140 (2012) 193– 196

Contents lists available at SciVerse ScienceDirect

Journal of Ethnopharmacology

journa l h o me page: www.elsev ier .com/ locate / je thpharm

thnopharmacological communication

alidation of self-reported khat chewing amongst khat chewers:n exploratory study

aba Kassima,∗, Aamenah Hawasha, Atholl Johnstonb, Ray Crouchera

Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Institute of Dentistry, 4 Newark Street, London E1 2AT, UKQueen Mary University of London, Barts and The London School of Medicine and Dentistry, William Harvey Research institute, John Vane Building, Charterhouse Square, LondonC1M 6BQ, UK

r t i c l e i n f o

rticle history:eceived 30 September 2011eceived in revised form5 November 2011ccepted 22 December 2011vailable online 8 January 2012

eywords:alidation

a b s t r a c t

Ethnopharmacological relevance: Khat chewing amongst the UK communities originating from Yemenand the East African coast is suggested to create dependency through its main stimulant components(cathinone, norephedrine and norpseudoephedrine) on the central nervous system.Aims of the study: To validate self-reported khat chewing behaviours by measuring levels of cathinone,norephedrine and norpseudoephedrine in saliva and to explore their associations with self-reported khatchewing dependency.Materials and methods: Face-to-face interviews were conducted amongst 30 male UK-resident khat chew-ers. Saliva samples were collected from each participant and high-performance liquid chromatography

hat chewing self-reportiomarkers

(HPLC) employed to extract and quantify the levels of the biomarkers.Results: The mean (SD) for cathinone and the composite norephedrine and norpseudoephedrine lev-els were 33.93 (±39.20) and 29.28 (±26.32) �g/mL respectively. These biomarkers were significantlyassociated (p ≤ 0.05) with khat chewing dependency.Conclusions: Validation of self-reported khat chewing is possible. Khat chewing dependency correlatessignificantly with biomarker levels in saliva. Replication is required.

. Introduction

Khat leaves have long been chewed in the Yemen and coun-ries of East Africa (Odenwald et al., 2010). Khat chewing releaseshe psychoactive agents cathinone, norephedrine and norpseu-oephedrine (Toennes et al., 2003). In countries producing khatuch as Yemen, use often starts at a young age, particularly amongstales (World Bank, 2007), and can develop into a compulsive daily

abit lasting a lifetime (Patel, 2000). This chewing habit contin-es within the global diaspora (Kassim and Croucher, 2006), and aange of oral and general health and socioeconomic impacts haveeen reported (Al-Motarreb et al., 2010).

Khat chewing’s potential to create psychological dependenceas been recently established in an exploratory study amongstK-khat chewers (Kassim et al., 2010). There is growing evidence

or physical dependence amongst habitual khat chewers (Kassimt al., 2010). Different varieties of khat have differing pharma-

ological compositions. Ethiopian Herari and Kenyan Mirra khatACMD, 2005) are readily available in the United Kingdom. Theotency of khat may be determined by its cathinone concentra-

∗ Corresponding author. Tel.: +44 (0) 207 8828664; fax: +44 (0) 207 882 5842.E-mail address: s.kassim@qmul.ac.uk (S. Kassim).

378-8741/$ – see front matter © 2012 Elsevier Ireland Ltd. All rights reserved.oi:10.1016/j.jep.2011.12.040

© 2012 Elsevier Ireland Ltd. All rights reserved.

tion (Kalix and Braenden, 1985). One of the main components ofkhat is. S-(−)-cathinone (S-(−)-�-aminopropiophenone, TN), alongwith the other main metabolites R,S-(−)-norephedrine (NE) andS,S-(+)-norpseudoephedrine (NPE, cathine) (Sporkert et al., 2003).

Cathinone is suggested to be a ‘natural’ amphetamine due tothe fact that both drugs are chemically alike with similar effectson the human body (Feyissa and Kelly, 2008). Khat chewers maynot like to admit dependence. Therefore, when dealing with self-reported data on drug use, it is fair to assume that a subjective biasexists (Jackson, 2000). The more negatively sanctioned a behaviourthe stronger the tendency to deny having engaged in it (Edwards,1958). The sufficiency and accuracy of self reported data on khatchewing behaviour may be questioned. Using self-report in con-junction with a simple, easy to administer method of validationis preferred as it eliminates discrepancies in the data and providesadditional assurance that the participants’ self-reports are accurate(SRNT, 2000).

Validation is the process of accumulating evidence to supportthe intended interpretation of collected results (Ford et al., 1997).This can be through medical records or biochemical tests, which

can confirm if the conclusions of the original data are actually true(Harrell, 1985). Different khat biochemical tests, including urine(Toennes and Kauert, 2002), blood (Beyer et al., 2007) and hair(Sporkert et al., 2003), have been reported. These methods have

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in SDS-khat scores were associated with increases in salivarybiomarker levels, rho = .424, p = 0.020 and rho = .415, p = 0.022 forcathinone and composite of norephedrine and pseudoephedrine,respectively (Fig. 1).

Table 1Mean rank and median of khat chewing biomarkers and severity of dependency onkhat chewing (SDS-khat).

Khat chewing biomarkers n Mean rank Median Sum of ranks p-Value

CathinoneSDS-khat

Up to 5 scores 17 10.68 5.700 181.50 0.0476 scores and above 7 16.93 65.500 118.50

Composite of norephedrine and

94 S. Kassim et al. / Journal of Ethn

isadvantages. Blood sampling is difficult, invasive and expensive,equiring a health professional to take the sample in sterile condi-ions (Cone, 1993).

Using saliva to validate khat use has been explored (Kassim,010), recognising that saliva detects current use and that theesults are comparable to blood (Toennes et al., 2005). Saliva alsoffers accessible, observable and non-invasive collection, althoughontamination should be considered (Cone, 1993).

This study aimed to validate self-reported khat chewingehaviours by measuring levels of cathinone, norephedrine andorpseudoephedrine in saliva and to explore their association withelf-reported khat chewing dependency.

. Materials and methods

.1. Study design, setting, sample size and selection

This cross sectional study recruited a convenience sample of 30ale khat chewers from three East London mafrishi. The sample

ize was chosen based on the study by Sporkert et al. (2003). Thearticipants were recruited consecutively over 6 weeks (April–May011) when they visited the mafrishi to either buy and/or chewhat.

.2. Data collection

Chewers present at the mafrishi were informed of the study andhose that consented were screened for eligibility for study partic-pation. Inclusion and exclusion criteria were reported in Kassimt al. (2010). Written informed consent was collected from eachf the participants and they were assured of confidentiality. Theelf-report data was collected through a face-to-face interview,sing a pre-piloted questionnaire that consisted of four sectionsKassim et al., 2010). Section one asked about the respondents’ocio-demographic characteristics (age, country of origin, level ofducation). Section two explored behavioural aspects of khat chew-ng (the type of khat usually chewed, how many bundles, if thisuantity had changed in the last year, the main reason for chewinghat, frequency and duration the khat sessions per week). Sec-ion three measured the participants’ dependence on khat chewingsing the Severity of Dependence scale (SDS-Khat) (Kassim et al.,010). Finally, section four asked about any accompanying tobaccose and whether this was regular or episodic (only smoked whenhey chewed khat). Twenty two participants were recruited fromne mafrishi.

Collection of saliva followed a standard protocol (ABS Labo-atories, personal communication). Participants placed a dentaloll in the mouth for approximately 2–10 min without chewing itntil it was saturated and was stored in a salivette. Samples wereirectly stored at −80 ◦C and assayed using high performance liq-id chromatography (HPLC). Quantitative analysis of saliva samplesor cathinone and norephedrine was carried out on liquid chro-

atography with tandem mass spectrometric detection (Sciex API000). Chromatographic separation was performed at 50 ◦C withupelcosil LC-SI column (5 �m, 10 cm × 4.6 mm ID). The mobilehase consisted of 75% methanol and 25% 10 mMol/L ammoniumcetate delivered as isocratic at 1 mL per minute. Quantitative mul-iple reaction monitoring (MRM) transitions for cathinone andtereoisomers:cathine (norpseudoephedrine) and norephedrineere 150.2/132.1 and 152.2/134.0, respectively. Simple sample

reparation method was adopted by diluting 10 �L of saliva sam-les/calibrators with 0.5 mL of 0.1% formic acid and 0.5 mL ofethanol in addition to 50 �L of internal standard (2.5 �g/mL of

orephedrin-D3). Finally, 10 �L of the mixture was injected into the

macology 140 (2012) 193– 196

liquid chromatography–tandem mass spectrometry (LCMS–MS)system.

This study was approved by the Queen Mary University of Lon-don Ethics Committee as an amendment of an approval by The EastLondon and City Health Authority Local Research Ethics Committeein 2007 (REC Ref. No. 05/Q06034/195).

2.3. Data analysis

Analysis was conducted using the Statistical Package for SocialSciences (SPSS) version 19. Descriptive and frequency analysisof the interview data was conducted first. The Chi-squared test(p ≤ 0.05) was used to inspect relationships between dependenceon khat chewing with behavioural khat chewing characteristics,and reasons for chewing khat. One biomarker outlier value wasadjusted to the nearest value. Correlation of salivary biomarkerswith khat dependency scores was inspected using spearman rhotest. The Mann–Whitney U test was used to inspect difference inmedian of biomarkers with khat dependency categories.

3. Results

3.1. Analysis of self-reported data

Participants mean (SD) age was 42 (±13) years. They were ofYemeni (46.7%) or Somali (36.7%) origin and 47% were universityeducated. The most common type of khat chewed by this sam-ple was Herari (57%). Mirra khat was preferred by 33% whilst 10%chewed a mixture of both kinds. Yemeni more likely (71%) chewedHerari khat whilst Somalis more likely chewed Mirra khat (67%).The principal reason for chewing was reported as being social inter-action. 63% of the sample chewed three or more days a week. Themean (SD) dependency score was 4.6 (±3.5), with 63% of the partic-ipants more likely dependent on khat (scores ≥6). The reasons forkhat chewing, along with the 10 composite khat behaviours werefound to have statistically significant associations (p ≤ 0.05) withkhat dependency.

4. Saliva sample analysis

Of the 30 participants, five did not consent to giving salivasamples and one sample was deemed insufficient to analyse. Ofthe remaining 24 samples, the mean (SD) cathinone concentrationwas 33.93 (±39.20) (median = 14.10, range 1–110.80) and 29.28(±26.32) (median = 26.45, range 1–74.90) �g/mL for norephedrineand norpseudoephedrine together. Statistically significant differ-ences (p ≤ 0.05) were found between khat dependency (SDS-Khat)median scores for the biomarker levels in saliva (Table 1). Increases

norpseudoephedrineSDS-khat

Up to 5 scores 17 10.53 7.000 179.00 0.0346 scores and above 7 17.29 46.800 121.00

S. Kassim et al. / Journal of Ethnopharmacology 140 (2012) 193– 196 195

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Fig. 1. Scatterplots of scores of khat chewing dependency with cathino

. Discussion

This study demonstrated for the first time that self reported khathewing is associated with raised levels of cathinone, norephedrinend pseudoephedrine in saliva. More dependent chewers wereore likely to have a significantly higher mean for the three

iomarkers.63% of study participants had an SDS-Khat score of 6 or higher,

ndicating dependence on khat chewing. The principal reason forhewing khat was social interaction. Dependence on khat chewingas found to be statistically significantly associated with reasons

or khat chewing and composite of khat chewing behaviour, con-rming findings from a previous study (Kassim et al., 2010). Thistudy found that respondents reported chewing because of socialnteraction whereas they chewed in a dependent manner on morehan 3 days each week (Nabuzoka and Badhadhe, 2000; Kassim androucher, 2006). Sykes et al. (2009) also states that chewing khat upo twice a week is regarded by chewers as normal social behaviour,ut that any greater frequency is problematic.

Future research should replicate this study, aiming to use aarger, more representative sample including female khat chew-rs to further investigate these findings. Exploring differences iniomarker levels through investigating separately different khatse and within different communities (Yemeni, Somali and Kenyan)ould establish an optimal cut off value for classifying dependent

nd non-dependent khat chewers. Simple, cheap, easy, feasible andcceptable methods of detecting khat biomarkers in saliva suchs the use of “dipstick” should be developed. Whilst cathinone inaliva is specific to khat chewing, its instability and decompositionnto norephedrine and pseudoephedrine may confound with usef dietary and cold drugs (Toennes and Kauert, 2002). According toarvis et al. (1987) amongst tobacco smokers there is no measurehat can be 100% sensitive to detecting smokers or identifying nonmokers. Until a reliable specific khat chewing biomarker is iden-ified khat chewers should be asked two questions: (a) whetherhere has been a recent common cold episode and (2) whethermphetamine derivatives were used to reduce weight. Further vali-ation research should seek to discriminate between khat use alonend khat use with either of these confounders.

Clinically, self-reported khat chewing status may not be suffi-ient, particularly in a situation where khat chewer is under strongressure to give up chewing. For example khat chewing is reportedo be associated with morbidity and co-morbidity, psychosis and

he use of health compromising substances, i.e. tobacco smokingWarfa et al., 2007; Kassim and Croucher, 2006). Validation of khathewing has great potential importance in the clinical managementf patients.

composite of norephedrine and norpseudoephedrine concentrations.

Study limitations include the sampling method and recruit-ing of most study sample participants from one site which mayhave contributed to elevated levels of these biomarkers andkhat dependency. Norephedrine and pseudoephedrine were notreported as separate entities. Nevertheless, the study has vali-dated self reported khat chewing, using a well established measurefor khat dependence and khat chewing behaviours (Kassim et al.,2010). Finally, results bias was eliminated as the assessor of salivabiomarkers was blinded to the outcomes investigated.

6. Conclusion

Validation of self-reported khat chewing is possible. Khat chew-ing dependency correlates significantly with biomarker levels insaliva. Replication is required.

Acknowledgements

We acknowledge the support of the East London Yemeniand Somali communities, especially Mr. Radwan Rahman whofacilitated our data collection. The support of Terry Lee at theBio-analytics Department at St George’s Hospital in the laboratoryanalysis of the samples is also acknowledged.

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