Urinary Cotinine and Nicotine Dependence Levels in Regular Male Electronic Cigarette Users

Objective: Found in plasma, urine, and saliva, cotinine can be used as a biomarker for nicotine in electronic cigarette (e-cig) users. Nicotine is addictive and causes dependence. Thus, it becomes a problem in smoking cessation programs. This study aimed to determine the relationship between urinary cotinine (UCot) and nicotine dependence levels in regular male e-cig users. Materials and Methods: This cross-sectional study consecutively included regular male e-cig users and non-smokers. All subjects were interviewed and had their UCot levels measured using an enzyme-linked immunosorbent assay method. The regular e-cig users completed the Penn State Nicotine Dependence Index questionnaire. Results: This study recruited 71 males aged 18-45 years divided into e-cig users and non-smokers group. The predominating characteristics in e-cig users are as follows: 23 males (67.6%) aged <30 years, the highest education of senior high school 25 (73.5%) and 25 (73.5%) subjects had occupation. The UCot levels among the e-cig users in the non-dependency group were lower than that of the medium-high dependency group (P=.008). The median value for UCot level in the regular e-cig users was higher than that of the non-smoker group (276.11 [58.01-284.15] ng/mL vs 5.21 [4.65-23.72] ng/mL, P<.001). Factors influencing the UCot levels of the e-cig users were age (P=.041), nicotine level of the e-cig liquid (P=.013), and the flavor of the e-cig liquid (eg, menthol or non-menthol; P=.040). Conclusion: UCot and nicotine dependence levels in the regular male e-cig users were significantly related. Nicotine dependence was found in 76.5% of the regular male e-cig users. The UCot levels in the e-cig users were significantly higher than in the non-smokers.