Racial differences in serum cotinine levels of smokers.

The purpose of this study was to estimate black/white differences in cotinine levels for current smokers of both sexes, and to explore the potential contribution of mentholated cigarettes to these differences. Sera from 255 current smokers sampled from Southern Community Cohort Study participants (65 black men, 65 black women, 63 white men, 62 white women) were analyzed for cotinine, and linear regression was used to model the effect of race on cotinine level, adjusting for the number of cigarettes smoked within the last 24 hours, use of menthol vs. non-menthol cigarettes, exposure to environmental tobacco smoke, and age. Black smokers smoked fewer cigarettes than white smokers, yet had crude mean cotinine levels nearly as high or higher than white smokers. After multivariate adjustment, cotinine levels were an average of 50 ng/ml higher among black than white women (p=0.008) and non-significantly 12 ng/ml higher among black than white men (p=0.52). We observed no increase in cotinine levels associated with menthol cigarette use. We conclude that differences in cotinine levels among smokers suggest racial variation in exposure to and/or metabolism of tobacco smoke constituents, but our findings do not support a role for menthol preference in this disparity.