Abstract
BACKGROUND AND AIMS: The time to first cigarette (TTFC) of the day is an indicator of nicotine intake in adults and adolescents. However, the relation between TTFC and biological markers of nicotine addiction and health risk in youths has not been well described. The current study examined whether an earlier TTFC predicts higher levels of a tobacco-specific carcinogen, 4-(methylnitrosamino)-1-(3-pyridal)-1 (NNAL), in regular and intermittent adolescent smokers and if this relation is mediated by nicotine intake (measured by cotinine) or cigarettes per day (CPD). DESIGN: A cross-sectional analysis of a nationally representative subsample of adolescents. SETTING: A general community sample from the 2007-08 and 2009-10 National Health and Nutrition and Examination Survey. PARTICIPANTS: A total of 215 adolescents in the United States between the ages of 12 and 19 years who reported smoking at least once in the 5 days prior to data collection. MEASUREMENTS: The primary outcome measure was urinary levels of NNAL. FINDINGS: In both regular and intermittent smokers, earlier TTFC was associated dose-dependently with higher levels of NNAL (P < 0.03 in both cases). TTFC had an indirect effect on NNAL, mediated by nicotine intake (cotinine) in both regular [β = -0.08, standard error (SE) = 0.03, 95% confidence interval (CI) = -0.15, -0.03] and intermittent (β = -0.02, SE = 0.01, 95% CI = -0.05, -0.002) smokers. CPD was not found to be an important mediator of the relation between TTFC and NNAL. CONCLUSIONS: Time between waking and the first cigarette of the day is correlated in daily and non-daily adolescent smokers with overall nicotine and therefore carcinogen intake.