[Relationship between vaping and smoking among 15-year-olds in high school. Results of a descriptive cross-sectional and monocentric observational study conducted in the metropolitan area of Saint-Étienne]. / Relations entre vapotage et tabagisme chez les adolescents en classe de seconde. Résultats d'une étude observationnelle descriptive transversale et monocentrique menée dans l'agglomération stéphanoise.

INTRODUCTION: The initiation of smoking among adolescents by vaping is a subject of controversy. This study focuses on the prevalence of electronic cigarette use among teenagers and its connection with the consumption of tobacco. METHODS: A cross-sectional and monocentric study was conducted in the spring of 2018 and included 1435 students (15-16years old) from the metropolitan area of Saint-Étienne in France. RESULTS: Nearly half of the adolescents experimented with e-cigarettes (50.30%) or tobacco (50.40%). Nearly a quarter are vapers (23.60%) or smokers (28.20%), with low daily use (3.65% for vaping and 9.40% for smoking). In regard to the link between smoking and vaping, 64.85% of adolescents are "non-smokers and non-vapers", 17.60% "smokers and vapers", 11.25% "smokers and non-vapers", and 6.30% "non-smokers and vapers". DISCUSSION: The portrait-types of the vaper and the smoker are similar: boy rather than girl, educated in private school rather than public, and enrolled in a vocational rather than a general educational course. On one hand, the use of electronic cigarettes in non-smoking adolescents does not appear to be a major mode of entry into smoking or nicotine addiction. On the other hand, the use of electronic cigarettes among adolescent's smokers seems to have a beneficial effect on their smoking habit (stopping or reducing the consumption of tobacco).