Time to First Cigarette and 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanol (NNAL) Levels in Adult Smokers; National Health and Nutrition Examination Survey (NHANES), 2007―2010

The time to first cigarette (TTFC) is a good indicator of several dimensions of nicotine dependence. An early TTFC is also associated with increased lung and oral cancer risk. Our objective was to determine the relationship between TTFC and exposure to tobacco smoke carcinogens. We conducted a cross-sectional analysis of a nationally representative subsample of smoking adults that had urinary samples analyzed for tobacco biomarkers. The study included 1,945 participants from the 2007-2008 and 2009-2010 National Health and Nutrition and Examination Survey. The main outcome measure was creatinine-adjusted urinary 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) levels. The cigarette-per-day adjusted levels of NNAL were twice as high in participants who smoked within 5 minutes after waking than in participants who refrained from smoking for at least 1 hour (0.58 vs. 0.28 ng/mL, P < 0.001). In multivariate linear models, a shorter TTFC was significantly associated with increasing NNAL levels, after adjusting for cigarettes smoked per day (or cotinine), secondhand smoke exposure, age, sex, race/ethnicity, and other potential confounders. These data show that in a nationally representative sample, there is a dose-dependent relationship between earlier smoking in the day and higher biologic exposure to a tobacco smoke carcinogen. Our study provides further evidence that highlights the relationship between TTFC, nicotine dependence, and cancer risk.