Revised and extended serum cotinine cut-offs to classify smokers and non-smokers

To revise and extend the previously published serum cotinine cut offs to classify smokers and non-smokers for US adolescents and adults.Cross-sectional data (N = 10171) from National Health and Nutrition Examination Survey for 2011-2014 were used to compute serum cotinine cut-offs to classify smokers and non-smokers for US adults aged ≥20 years and 2007-2014 (N = 4583) data were used to compute serum cotinine cut-offs for US adolescents aged 12-19 years.Specificities and sensitivities for the cut-offs among adults were ≥95% and ≥75% among adolescents. For adults, serum cotinine cut-offs in ng/mL to classify smokers from non-smokers were 3.3 for the total population, 4.13 for males, 2.99 for females, 4.03 for non-Hispanic whites, 8.85 for non-Hispanic blacks, 0.377 for Mexican Americans, 1.72 for other Hispanics and 1.41 for non-Hispanic Asians. For adolescents, serum cotinine cut-offs in ng/mL to classify smokers from non-smokers were 0.765 for the total population, 1.1 for males, 0.408 for females, 1.2 for non-Hispanic whites, 1.98 for non-Hispanic blacks, 0.215 for Mexican Americans and 0.321 for other Hispanics.Serum cotinine cut-offs to distinguish smokers from non-smokers for US adults and adolescents were developed.