E-cigarette use, dual use of e-cigarettes and tobacco cigarettes, and frequency of cannabis use among high school students

Background: The proliferation of electronic vaping products raises many concerns, including whether these products will lead to risky behaviors among adolescents. Evidence suggests that e-cigarettes may be used to vaporize cannabis (marijuana). The current study examined associations between e-cigarette use, dual use of e-cigarettes and tobacco cigarettes, and frequency of cannabis use. Methods: Data on high school students (grades 9-12) were from the 2014-2015 Canadian Student Tobacco, Alcohol and Drugs Survey (n = 23,429 respondents). Multinomial logistic regression analyses were used to examine frequency of cannabis use among those who reported using only e-cigarettes, only tobacco cigarettes, both products, and nonusers. Results: Approximately 15% of respondents reported using cannabis at least once in the past month. Likelihood of using cannabis was significantly higher for e-cigarette only and cigarette-only users. Users of both products had increased odds for a higher frequency of cannabis use. These results indicated a sequential risk gradient in the use of cannabis for dual use, cigarette only, e-cigarette only, and non-use groups, respectively. Conclusions: Youth who reported use of e-cigarettes, tobacco cigarettes, and both products showed a heightened risk of using cannabis more frequently.