E-cigarettes, conventional cigarettes, and dual use in Korean adolescents and university students: Prevalence and...

To examine risk factors associated with use of e-cigarettes only, conventional cigarettes only, and dual use in Korean adolescents and young adults.

In a cross-sectional study, anonymous questionnaires were completed between April-May, 2015 among 1) 2744 middle and high school students, aged 13-18, from Seoul, Incheon, Gyeonggi, and Cheongju, Korea and 2) 2167 university students, aged 19-29, from fourteen universities in Korea.

The results show that 12.6% of adolescents and 21.2% of university students reported having ever tried e-cigarettes at least once. Among the ever e-cigarette users, 95.1% and 96.3% of adolescents and university students also tried conventional cigarettes, respectively. Dual users were more likely to be male (adolescents: OR 2.63, 95% CI 1.93-3.57; university students: 4.28, 3.21-5.70), have any close friends who smoke (adolescents: 11.56, 7.63-17.53; university students: 11.29, 5.52-23.10), have any siblings who smoke (adolescents: 3.17, 2.25-4.46; university students: 1.78, 1.30-2.43), and have observed teachers smoke cigarettes at school (adolescents: 1.45, 1.05-2.01).

A majority of e-cigarette users were dual users. Friends' and siblings' smoking status were significantly associated with dual product use in adolescent and young adult populations. Surveillance of e-cigarette use and implementation of evidence-based behavioral interventions targeting adolescents and young adults are necessary.