Table 1 Selected baseline characteristics of genotyped White ever-smokers, according to whether they had inhaled at cohort inception. NDIT 1999–2012.
All inhalers (inhaled before cohort inception or during follow-up) n = 420–421
Incident inhalers (inhaled during follow-up) n = 214
Ranges in values represent the values derived from the 10 imputed datasets.
Table 2 Hazard ratios (HR) and 95% confidence intervals (CI) for ICD-10 tobacco dependence in adolescent smokers according to CYP2A6 and CYP2B6 metabolism groups. NDIT 1999–2012.
Includes prevalent (i.e., those who had inhaled before cohort inception) and incident (i.e., those who first inhaled during follow-up) inhalers.
Table 3 Frequency of early smoking experiences among participants who inhaled, according to CYP2A6 and CYP2B6 metabolism group. NDIT 1999–2012.
Includes prevalent (i.e., those who had inhaled before cohort inception) and incident (i.e., those who first inhaled during follow-up) inhalers.
Nausea and dizziness was indicated by the response “a lot” or “a bit” (vs. “not at all”) when participants were asked about experiencing these symptoms the first time they smoked.
P values are derived from chi-square tests.
Table 4 Linear regression analysis of past month cigarette consumption at end of follow-up among participants who initiated inhalation during follow-up, according to dependence status and CYP2A6 and CYP2B6 metabolism group. NDIT 1999–2012.
Note: Coefficients for CYP2A6 intermediate and CYP2A6 slow metabolizers are expressed relative to CYP2A6 normal metabolizers, while coefficients for CYP2B6 slow metabolizers are expressed relative to CYP2B6 normal metabolizers. For example, in the unadjusted model in the dependent smokers, CYP2A6 slow metabolizers smoked 108 fewer cigarettes compared to CYP2A6 normal metabolizers. Abbreviations: CI, confidence interval.
The regression coefficients and 95% confidence interval are reported, derived from 10 imputed datasets.
Covariates included: sex, age, time since first inhalation.
Intercept in regression.
Fig. 1. Self-reported smoking behaviours are strongly associated with salivary cotinine levels in young adults. Correlation between self-reported cigarettes/month and cotinine, demonstrating construct-related validity, is shown in (A). Correlations between cotinine and ICD-10 (B) and mFTQ (C) dependence scores, withdrawal (D), other nicotine dependence symptoms (E), and self-medication (F) scores are also shown in all White self-reported current smokers (n = 162).