The influence of electronic cigarette age purchasing restrictions on adolescent tobacco and marijuana use.

Objective: In the United States, many states have established minimum legal purchase ages for electronic nicotine delivery systems (ENDS) to ban adolescent purchases, but these policies may also affect other related substance use. We explore whether ENDS are substitutes or complements for cigarettes, cigars, smokeless tobacco, and marijuana among adolescents by using variation in state-level implementation of ENDS age purchasing restrictions.

Methods: We linked data on ENDS age purchasing restrictions to state- and year-specific rates of adolescent tobacco and marijuana use in 2007-2013 from the Youth Risk Behavior Surveillance System.