Association between Peer Cigarette Smoking and Electronic Cigarette Smoking among Adolescent Nonsmokers: A National Representative Survey

We assessed the association between electronic cigarette (e-cigarette) use and peer cigarette smoking, a major risk factor for the initiation of cigarette smoking in adolescents. Data from the 2013 Korea Youth Risk Behavior Web-based Survey of 65,753 nonsmokers aged 13-18 years were analyzed using multiple logistic regression. A total of 3.8% of the Korean adolescents were 'ever e-cigarette' users and 1.2% were current users. Adjusted odds ratios (ORs) for current and ever e-cigarette use compared to those whose closest friends were non-smokers ranged from 2.05 (95% confidence interval [CI], 1.82-2.30) to 5.50 (95% CI, 4.77-6.34), and from 2.23 (95% CI, 1.77-2.81) to 7.82 (95% CI, 5.97-10.25) for those who had 'some' close friends to 'most/all' friends who smoked, respectively. The slopes of the adjusted ORs for e-cigarette use in 'never smokers' were more than twice as steep as those in 'former smokers', showing a significant interaction effect between the proportion of smoking closest friends and cigarette smoking status (never or former smokers) (p<0.001 for interaction). Peer cigarette smoking had a significant association with e-cigarette use in adolescent nonsmokers, and this association was greater on never smokers than former smokers.