title: The influence of electronic cigarette age purchasing restrictions on adolescent tobacco and marijuana use.
abstract: 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.
  
  
  
  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. This data provides a nationally representative sample of adolescents who attend public and private schools. We performed a fixed effect regression analysis exploring the influence of ENDS age purchasing restrictions on outcomes of tobacco use and marijuana use, controlling for state and year fixed characteristics, age-race cohorts, cigarette excise taxes, and cigarette indoor use restrictions.
  
  
  
  For cigarette use, we separate our results into cigarette use frequency. We found causal evidence that ENDS age purchasing restrictions increased adolescent regular cigarette use by 0.8 percentage points. ENDS age purchasing restrictions were not associated with cigar use, smokeless tobacco use, or marijuana use.
  
  
  
  We document a concerning trend of cigarette smoking among adolescents increasing when ENDS become more difficult to purchase.
authors.affiliation: Department of Healthcare Policy and Research, Weill Cornell Medical College, Cornell University, LA-216, 402 East 67th Street, New York, NY 10065, USA. Electronic address: mip2037@med.cornell.edu.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Pesko
authors.affiliation: Department of Healthcare Policy and Research, Weill Cornell Medical College, Cornell University, LA-216, 402 East 67th Street, New York, NY 10065, USA.
authors.forename: Jenna M
authors.initials: JM
authors.lastname: Hughes
authors.affiliation: Department of Healthcare Policy and Research, Weill Cornell Medical College, Cornell University, LA-216, 402 East 67th Street, New York, NY 10065, USA.
authors.forename: Fatima S
authors.initials: FS
authors.lastname: Faisal
mesh_terms: D000293:Adolescent; D000367:Age Factors; D003132:Commerce / Q000331:legislation & jurisprudence*; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D006801:Humans; D008385:Marijuana Smoking; D012907:Smoking; D011795:Surveys and Questionnaires; D062789:Tobacco Products; D014030:Tobacco, Smokeless; D014481:United States
keywords: E-cigarettes; Electronic nicotine delivery systems; Minimum legal purchase age; Tobacco control