Background: Although nicotine dependence plays a role as a main barrier for smoking cessation,there is still a lack of solid evidence on the validity of biomarkers to determine nicotine dependence inclinical settings. This study aimed to investigate whether urinary cotinine levels could reflect the severityof nicotine dependence in active smokers. Materials and Methods: Data regarding general characteristicsand smoking status was collected using a self-administered smoking questionnaire. The Fagerström test fornicotine dependence (FTND) was used to determine nicotine dependence of the participants, and a totalof 381 participants were classified into 3 groups of nicotine dependence: low (n=205, 53.8%), moderate(n=127, 33.3%), and high dependence groups (n=49, 12.9%). Stepwise multiple linear regression modeland receiver operating characteristic (ROC) curves analyses were used to determine the validity of urinarycotinine for high nicotine dependence. Results: In correlation analysis, urinary cotinine levels increasedwith FTND score (r=0.567, P<0.001). ROC curves analysis showed that urinary cotinine levels predicted thehigh-dependence group with reasonable accuracy (optimal cut-off value=1,000 ng/mL; AUC=0.82; P<0.001;sensitivity=71.4%; specificity=74.4%). In stepwise multiple regression analysis, the total smoking period(β=0.042, P=0.001) and urinary cotinine levels (β=0.234, P<0.001) were positively associated with nicotinedependence, whereas an inverse association was observed between highest education levels (>16 years) andnicotine dependence (β=-0.573, P=0.034). Conclusions: The results of this study support the validity of usingurinary cotinine levels for assessment of nicotine dependence in active smokers.
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