Nicotine Dependence Evaluated by Urinary Cotinine and Heaviness of Smoking Index among Smokers, Vapers, and Dual Users: A Cross-Sectional Study Using the Korea National Health and Nutrition Examination Survey Data

BACKGROUND: Many people use both combustible cigarette (CC) and electronic cigarette (EC). We compared nicotine dependence among CC, EC, and dual users using questionnaires and urinary cotinine levels. METHODS: Data from the Korea National Health and Nutrition Examination Survey (2014–2017) databases were analyzed; 3,917 CC, EC, and dual users were administered the urinary cotinine test, and 1,045 current CC and dual users completed the Heaviness of Smoking Index (HSI) questionnaires. Weighted geometric means of urine cotinine levels were compared between exclusive CC, exclusive EC, and dual users. The distribution rate, based on time to first cigarette (TTFC), cigarettes per day (CPD), and the HSI was analyzed in two weighted groups, exclusive CC and dual users. RESULTS: Among those who currently use any type of cigarette, 89.4%, 1.4%, and 9.2% were exclusive CC, exclusive EC, and dual users, respectively. Weighted geometric means of urine cotinine were highest in dual users (1,356.4 ng/mL), followed by exclusive CC (1,270.3 ng/mL), and exclusive EC (867.7 ng/mL) with significant differences between all three groups (P<0.05). There were no statistically significant differences in CPD between exclusive CC and dual users (P=0.626). The proportion of TTFC ≤5 minutes was 21.5% and 29.5% in the two groups, respectively (P=0.010); however, HSI differences in the two groups was marginal (P=0.557). CONCLUSION: In this study, the urinary cotinine value could distinguish the three groups, CC, EC, and dual users, but the questionnaire using HSI could not distinguish the three groups.