Initial responses to the first dose of nicotine in novel smokers: the role of exposure to environmental smoking and genetic predisposition.
BACKGROUND
Sensitivity to initial smoking constitutes an early predictor of the risk of dependence. We investigated the role of exposure to smoking (by parents, siblings, and peers) and reward-related candidate gene polymorphisms (OPRM1 A118G, DRD2 TaqlA and DRD4 bp VNTR) in adolescents' responses to initial smoking.


METHODS
We used cross-sectional survey data and saliva samples from 171 Dutch students who had never inhaled on a cigarette (mean age: 13.9 years). The outcome measure was adolescents' self-reported responses to initial smoking.


RESULTS
Exposure to peer smoking was associated with increased liking (OR = 1.74, CI = 1.13-2.70) and more pleasant sensations (β = .21, p = .01). Exposure to maternal smoking was associated with less unpleasant sensations (β = -.20, p = .01). Adolescents carrying the G-variant of the OPRM1 A118G polymorphism were more likely to report liking (OR = 2.50, CI = 1.09-5.73) and adolescents homozygous for the C-variant of the DRD2 TaqlA polymorphism reported less unpleasant sensations (β = .18, p = .04).


CONCLUSIONS
Although preliminary, these findings suggest that exposure to environmental smoking and polymorphisms in the OPRM1 and DRD2 gene may affect initial sensitivity to nicotine, an early phenotype of the risk of dependence. In the future, collaborative efforts to combine data from multiple studies in meta-analyses are needed to improve accuracy of estimated effects in genetic studies.
a Behavioural Science Institute, Radboud University Nijmegen , Nijmegen , The Netherlands.
Kathrin
K
Schuck
Roy
R
Otten
Rutger C M E
RC
Engels
Marloes
M
Kleinjan
D000293:Adolescent; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D009426:Netherlands; D009538:Nicotine / Q000008:administration & dosage*; D010290:Parents / Q000523:psychology; D010379:Peer Group; D011110:Polymorphism, Genetic; D017448:Receptors, Dopamine D2 / Q000235:genetics; D017450:Receptors, Opioid, mu / Q000235:genetics; D012201:Reward; D012907:Smoking / Q000235:genetics* / Q000523:psychology*; D014029:Tobacco Use Disorder / Q000235:genetics*
C581293:DRD2 protein, human; C485764:OPRM1 protein, human; D017448:Receptors, Dopamine D2; D017450:Receptors, Opioid, mu; D009538:Nicotine