What differentiates youths who use e-cigarettes from those who smoke traditional tobacco products?

<bold>Background: </bold>Electronic cigarette (e-cigarette) use has spread among adolescents in many countries, however users' characteristics are not well known. We aimed to compare characteristics of exclusive e-cigarette users to those of exclusive tobacco users and dual users.<bold>Methods: </bold>Data come from a representative sample of 11-19 years old students in Paris, surveyed each year between 2013 and 2017. Current e-cigarette and tobacco use were ascertained in the preceding 30 days. Data were analyzed using random intercept multinomial logistic regression models, exclusive tobacco smokers being the reference group.<bold>Results: </bold>Among the 17,435 students included, 2.3% reported exclusive e-cigarette use, 7.9% exclusive tobacco use and 3.2% dual e-cigarette and tobacco use. Compared to exclusive tobacco smokers, e-cigarette users were: a) less likely to use cannabis (adjusted Odds-Ratio (aOR) = 0.15, 95% confidence interval (95% CI) = 0.09-0.25); b) more likely to initiate smoking with an e-cigarette or a hookah rather than traditional cigarettes (aOR = 2.91, 95% CI = 1.74-4.87 and aOR = 15.99, 95% CI = 8.62-29.67, respectively). Additionally, exclusive e-cigarette users are younger with an aOR = 0.29 (95% CI = 0.17-0.49) among 13-15 years and aOR = 0.11 (95% CI = 0.06-0.21) among > 17 years as compared to 11-13 years. The probability of being an exclusive e-cigarette user is lower among participants whose best friend smokes tobacco (aOR = 0.30, 95% CI = 0.20-0.44). Exclusive tobacco users and dual users have similar profiles.<bold>Conclusions: </bold>Adolescents who only used e-cigarettes had intermediate levels of risk compared to nonusers and those who used tobacco and/or e-cigarettes, suggesting that e-cigarettes use extends to young people at low-risk of using tobacco products. [ABSTRACT FROM AUTHOR]