Electronic cigarettes (e-cigarettes), sold since 2010 in many countries including France, have become widely used among adults, particularly by older smokers trying to quit or decrease tobacco use. E-cigarettes are also getting popular among adolescents. Yet, factors associated with e-cigarettes use among youth are not well known. The objective of this study is to compare characteristics of adolescents who are exclusive e-cigarettes to those who exclusively use tobacco and to those who use both tobacco and e-cigarettes.

We test individual and social factors distinguishing e-cigarette and tobacco use among 12 to 19 years olds participating in the “Paris sans Tabac” (Smokeless Paris, PST) study, a yearly repeated cross-sectional survey conducted among secondary school students in Paris, France between 2013 and 2017. Junior high schools (n=9017) and high-schools (n=8418) in Paris were selected based on a clustered sampling design; quotas were then applied to balance school levels and characteristics. Each year approximately 3500 students were included in the study. Students completed self-reported questionnaires assessing demographic, individual, family smoking characteristics as well as their own tobacco, alcohol, cannabis and e-cigarette use. Current e-cigarette or tobacco use was defined as use in the preceding 30 days. Data were analyzed using marginal multinomial logistic regression models in which tobacco smokers who did not use e-cigarettes served as the reference group.

In total, 17,435 students with complete data (median age 16 years) were included across five study waves. Au total, 2.3% (n=392) students reported exclusive e-cigarette use, 7.9% (n=1370) tobacco use without e-cigarette use and 3.2% (n=555) tobacco and e-cigarette use. Compared to current tobacco smokers who did not use e-cigarettes, current e-cigarette users were more likely to have initiated smoking using an e-cigarette or water-pipe rather than cigarettes (adjusted Odds-Ratio [OR] OR=9.59, 95% CI=4.81–19.13 and OR=2.27, 95% CI=1.23–4.20, respectively) and less likely to use cannabis (OR=0.12, 95% CI=0.06–0.23). Other factors associated with a low probability of being an exclusive e-cigarette user were age (OR=0.28, 95% CI=0.14–0.55 among 14–16 years old, OR=0.12, 95% CI=0.06–0.24 among≥17 year old vs. 11–13 years old), having a best friend who is a smoker or former smoker (OR=0.35, 95% CI=0.23–0.56). Exclusive tobacco use was associated with survey year, alcohol consumption, perception of peer smoking and parental ban on smoking. Compared to tobacco smokers who did not use e-cigarettes, tobacco smokers who concurrently used e-cigarettes were more likely to use cannabis (OR=1.84, 95% CI=1.24–2.73) and older (OR=0.39, 95% CI=0.21–0.72 among≥17 year old vs. 11–13 years old). We found no statistically significant school effect.

Adolescents who exclusively use e-cigarettes differ from those who use tobacco, with or without e-cigarettes. The strongest discriminating factors between these groups are (1) the product of smoking initiation, (2) cannabis use, (3) age and peers’ smoking status. We found no identifiable differences between tobacco users using or not e-cigarettes, with the notable exception of concurrent cannabis use. Future studies need to examine the way in which these profiles evolve over time.