Nicotine metabolism and addiction among adolescent smokers
Aims The purpose of this study was to determine the association between the nicotine metabolic rate and smoking behavior, including addiction, in adolescent smokers. Design Baseline data from a prospective study of adolescent smoking behaviors and nicotine metabolism. Setting The setting was an out-patient university hospital in San Francisco. Participants Adolescent smokers (n = 164) aged 13–17 years old. Measurements Participants completed self-report measures of smoking behavior and nicotine dependence (modified Fagerström Tolerance Questionnaire: mFTQ). The nicotine metabolite ratio (NMR), a phenotypic marker of the rate of nicotine metabolism, was calculated using the ratio of concentrations of deuterium-labeled 3′-hydroxycotinine to cotinine-d4. Findings Participants reported smoking a mean of 2.86 cigarettes per day (CPD) [median = 1.78, standard deviation (SD) = 3.35] for 1.37 years (median = 1.0, SD = 1.36). Results from multivariate analyses accounting for age, race/ethnicity, gender and duration of smoking indicated that slower metabolizers smoked more CPD than faster metabolizers (the NMR was inversely related to CPD; P = 0.02). Slower metabolizers also showed greater dependence on the mFTQ (NMR was negatively associated with the mFTQ; P = 0.02). Conclusions In adolescence, slower clearance of nicotine may be associated with greater levels of addiction, perhaps mediated by a greater number of cigarettes smoked.