Abstract
Objectives : Cotinine, the major metabolite of nicotine, is a useful marker of exposure to tobacco smoke and self-reporting of smoking status is thought not to be reliable. This study aimed to evaluate the agreement between the smoking self-report among adolescents and the urinary cotinine test. Methods : The study subjects were 1226 middle and high school students in Hanam city, who were selected by stratified random sampling. The self-report about smoking behavior was compared with urine cotinine value measured with PBM $AccuSign^{\circledR}fi$ Nicotine(Princeton BioMeditech Corporation, USA). The percentage agreement, kappa and 95% confidence interval(CI) were calculated. Results : The overall percentage agreement was 88.6%, and those for boys, girls, middle school, general school and vocational school students were 87.3%, 90.1%, 93.7%, 85,5%, 90.7%, and 78.4%, respectively. The overall kappa index was 0.46(95% CI=0.39-0.54)for overall, .and those for boys, girls, middle school, general school and vocational school students were 0.56(95% CI=0.48-0.65), 0.20(95% CI=0.07-0.32), 0.21(95% CI=0.09-0.34), 0.55(95% CI=0.47-0.64), 0.42(95% CI=0.33-0.52), and 0.48(95% CI=0.36-0.60), respectively. Conclusion : The percentage agreement was relatively high but the kappa values very low for girls, and middle school students. Though the prevalence bias can be influenced by these results, the self-report was not a sufficient tool for the evaluation of adolescents' smoking status, especially in girls or middle school students.