The study sought to determine e-cigarette use prevalence and its relation to alcohol use as a potential gateway drug, and how this may differ by sex and ethnicity in a multi-ethnic sample of California adolescents. Authors included data from 1,806 adolescents ages 12 to 17 years in the 2014 and 2015 California Health Interview Survey (CHIS) cycles. The prevalence of e-cigarette use was calculated within sex and ethnic groups and the prevalence of alcohol use according to e-cigarette use was also examined with sample weighting providing population estimates.

Multiple logistic regression models were built to predict the odds of using alcohol from e-cigarette use status adjusted for socio-demographic and other characteristics. The prevalence of e-cigarette use was 9.1 percent overall in California adolescents but highest in boys among non-Hispanic whites (15.1 percent) and in Asian girls (13.3 percent). Among e-cigarette users, 61.3 percent of boys and 71 percent of girls reported using alcohol as well. The logistic regression odds of alcohol use, adjusted for age, ethnicity, body mass index, cigarette smoking status, socioeconomic status, parents' education level, and insurance status among e-cigarettes users (compared with non-users) was 9.2 in girls and 3.1 in boys. Asians/others, non-Hispanic whites and Hispanics were similarly at increased odds: 17.8, 5.4, and 3.0, respectively of using alcohol compared with their non-e-cigarette using counterparts, respectively.