Licit and Illicit Substance Use by Adolescent E-Cigarette Users Compared with Conventional Cigarette Smokers, Dual Users, and Nonusers

Purpose Compare the lifetime prevalence of eight forms of substance use (alcohol, drunkenness, oral tobacco, snuff, sleeping pills/tranquilizers, sniffed glue, marijuana, and amphetamine) among adolescent e-cigarette (EC) users, conventional cigarette (CC) smokers, dual users, and nonusers. Methods We analyzed population-level school-survey data collected from 10th-grade students (aged 15-16 years) in February 2015 in Iceland (N = 3,477; response rate, 84.4%). Results Smoking rates were similar for both sexes. Around 17% had used ECs and almost 8% had used ECs and not combustible tobacco, 5%-6% had smoked CCs but not ECs, around 9% were dual users. EC-only users were significantly more likely than nonusers to have used the eight substances investigated in the study but were less likely to have used these substances than CC smokers and dual users. Conclusion The four groups assessed in this study appear to form a sequential risk gradient to the use of other substances.