Variation in nicotine intake among U.S. cigarette smokers during the past 25 years: evidence from NHANES surveys.

OBJECTIVE:To estimate changes in nicotine intakes among U.S. cigarette smokers from 1988 to 2012 with the National Health and Nutrition Examination Survey (NHANES). METHODS:NHANES provides data on nationally representative samples of cigarette smokers from the civilian noninstitutionalized U.S. population. A total of 4,304 smokers aged 20 years and older were studied in NHANES III 1988-1994 and 7,095 were studied in the continuous NHANES 1999-2012. We examined serum cotinine concentrations, daily cigarette consumption, and estimated nicotine intake per cigarette, with adjustment for sex, age, racial/ethnic background, level of education, and body mass index. RESULTS:There was little overall change in nicotine intake from smoking cigarettes either in the U.S. population as a whole or in major racial/ethnic subgroups during the 25-year period from 1988. Serum cotinine averaged 223.7ng/mL (95% confidence interval [CI] = 216.1-231.3) in 1988-1994, which was not significantly different from the adjusted mean of 219.2ng/mL (95% CI = 214.1-224.4) in 1999-2012. During the same period, average daily cigarette consumption declined substantially, from 17.3 (95% CI = 16.5-18.0) in 1988-1994 to 12.3 (95% CI = 11.0-13.6) by 2012. Cotinine per cigarette smoked increased by some 42% between 1988-1994 and 2011-2012, from a geometric mean of 12.4 (95% CI = 11.7-13.1) to 17.6 (95% CI = 16.1-19.2). CONCLUSIONS:Reductions in cigarette smoking prevalence since the late 1980s, changes in cigarette product design, and the widespread introduction of smoke-free policies have not had a significant impact on nicotine intakes among U.S. smokers. Reductions in cigarette consumption have been offset by increased nicotine intake per cigarette smoked.