Concurrent E-cigarette and marijuana use and health-risk behaviors among U.S. high school students.

The use of electronic cigarettes (e-cigarettes) and marijuana remain prevalent problems among adolescents nationwide. We assessed current (past 30-day) exclusive e-cigarette use, exclusive marijuana use, and concurrent use with unintentional injury and violent behaviors, alcohol and other drug use behaviors, and sexual behaviors among U.S. high school students. We analyzed 2017 Youth Risk Behavior Survey data including 12,578 high school students nationwide. Multivariable logistic regression models were performed to compare these health-risk behaviors among exclusive e-cigarette users, exclusive marijuana users, and concurrent users with non-users among the overall sample, and then to compare exclusive e-cigarette users and exclusive marijuana users with concurrent users among current users only. All models adjusted for adolescent sex, grade, and race/ethnicity, and other tobacco product use. Approximately 77% of students were non-users, 5.2% were exclusive e-cigarette users, 9.9% were exclusive marijuana users, and 7.8% were concurrent users. Compared to non-users, exclusive e-cigarette users and exclusive marijuana users were more likely to engage in most negative health-risk behaviors associated with unintentional injuries and violence, alcohol and other drug use, and sexual behaviors. Among current users only, exclusive e-cigarette users and exclusive marijuana users were at reduced odds of engaging in most of these health-risk behaviors when compared to concurrent users of both substances. The relationship between exclusive and concurrent e-cigarette and marijuana use and health-risk behaviors highlights the importance of comprehensive educational efforts during high school. Findings suggest need for more studies on influence of e-cigarette and marijuana use on injury and violence risk among youth.