Time to First Cigarette and Serum Cotinine Levels in Adolescent Smokers: National Health and Nutrition Examination Survey, 2007-2010

Introduction: Nicotine dependence and uptake among adolescents remains challenging to characterize and measure. Among adults, a shorter time to the first cigarette after waking up in the morning (TTFC) has become increasingly recognized as an indicator of nicotine dependence because of its association with biological measures of nicotine exposure, smoking relapse, and failed cessation attempts. However, the relation between TTFC and these measures has not been studied among adolescents. This study explored the association between TTFC and cotinine among adolescent smokers.

Methods: The study utilized 2007-2008 and 2009-2010 National Health and Nutrition Examination Survey (NHANES) data from 220 regular adolescent smokers between the ages of 12 and 19 who provided blood samples for cotinine evaluation. Regression modeling was conducted to determine whether TTFC predicts cotinine levels, a marker of nicotine uptake.

Results: The time to first cigarette was significantly correlated with several smoking behaviors including number of cigarettes per day, time since last cigarette, and having a family member who smokes at home. Mean cotinine levels were more than 200 ng/ml in youths who smoked within 5 min after waking, compared with less than 34 ng/ml in youths who waited for more than 1 hr. In multiple regression models, a shorter time to first cigarette predicted higher cotinine levels after controlling for number of cigarettes per day and other factors. The TTFC was a predictor of cotinine for both male and female smokers.

Conclusion: The TTFC is a strong indicator of nicotine dependence in adolescents and could be an important component in screening for high-risk smoking and the development of tailored adolescent smoking intervention programs.