Re-visiting serum cotinine concentrations among various types of smokers including cigarette only smokers: some new, previously unreported results.

Data (N = 11614) from National Health and Nutrition Examination Survey (NHANES) for 1999-2016 for US adults aged ≥ 20 years were analyzed by fitting regression models to estimate unadjusted and adjusted geometric means (AGM) for several different groups of smokers. Serum cotinine level ≥ 3.3 ng/mL was used to distinguish smokers from nonsmokers. AGMs for cigarette only, cigar only, dual cigarette/cigar, e-cigarette or dual e-cigarette/cigarette, and smokeless tobacco only smokers were estimated to be 152.5, 65.1, 92.5, 146.3, and 272.0 ng/mL, respectively. Males were found to have higher cotinine levels than females for dual cigarette and cigar smokers, but the reverse was observed for smokeless tobacco users. Non-Hispanic blacks had higher AGMs than non-Hispanic whites for cigarette only smokers, but the reverse was observed for dual cigarette and cigar smokers. For the first time, serum cotinine estimates for those self-reported nonsmokers who were classified to be smokers (29.4 ng/mL) and those smokers for whom self-reported data for use of tobacco products were missing were also estimated (113.8 ng/mL).