Background: The dual use of combustible and electronic cigarettes is gaining popularity among adolescents, but little is known about their dual use. This study aimed to evaluate the trend of changes in the prevalence of dual users and to investigate associated factors with the dual use. Methods: Using data from the 2016-2018 Korean Youth Risk Behavior Survey, the frequency of smoking, electronic cigarette use, and dual use was assessed among students aged between 13 and 18 years old. Using the date between 2016 and 2017, multivariate logistic regression analysis was conducted to evaluate associated factors related to the dual use among 7,781 current smokers. Results: The dual use of both combustible and e-cigarettes was increased from 2.94% in 2016 to 3.32% in 2018 although smoking prevalence was at a steady state in male students. The dual user proportion of male current smokers was changed from 30.4% in 2016 to 35.4% in 2018. Those who had experienced illegal drug use are more likely to be dual user of conventional tobacco and electronic cigarette than those who did not experienced illegal drug use (aOR 2.05, 95% CI 1.50-2.80 in male; aOR 5.03, 95% CI 1.50-2.80 in female). Smoking amount was an important associated factor of dual use among adolescents, while alcohol drinking and depressive mood were important factors of dual use in male adolescent only. Conclusion: The dual use of both conventional and electronic cigarettes has been an increasing prevalence among adolescents after 2016, with several important factors such as illegal drug use and smoking amount.

Electronic cigarette, Dual use, Adolescent, Nicotine dependence