A Link Between E-Cigarette Use and Marijuana Use Among Adolescents and Young Adults

The results of a new study suggest a link between e-cigarette use and marijuana use among adolescents and young adults. The findings were published in JAMA Pediatrics.

In this study, researchers combed databases including PubMed, Embase, and Web of Science & ProQuest Dissertations for studies that compared rates of marijuana use among youth between the ages of 10 and 24 years old who had used e-cigarettes vs those who had not from inception to October 2018. They also searched gray-literature for conference abstracts, government reports, and other sources. All studies were independently extracted and evaluated by two reviewers following the standards of Meta-analyses of Observational Studies in Epidemiology (MOOSE).

The researchers implemented the Newcastle-Ottawa Scale to evaluate all data for quality. The study’s main measures and endpoints were adjusted odds ratios (AORs) and youth who use marijuana with and without a prior history of smoking e-cigarettes. Overall, the searchers identified 835 studies, of which 21 (2.5%) met inclusion criteria. These studies comprised 128,227 participants.

A Troubling Correlation 

According to the results of the study, the odds of marijuana use were higher in youth who had an e-cigarette use history juxtaposed to those who did not (AOR=3.47 [95% CI, 2.63 to 4.59]; I², 94%). The study also showed that marijuana use was notably higher in youth who used e-cigarettes in both longitudinal studies (3 studies; AOR=2.43 [95% CI, 1.51 to 3.90]; I², 74%) and cross-sectional studies (18 studies; AOR=3.70 [95% CI, 2.76 to 4.96]; I², 94%). Moreover, the odds of using marijuana in youth with e-cigarette use were higher in adolescents aged 12 to 17 years (AOR=4.29 [95% CI, 3.14 to 5.87]; I², 94%) than young adults aged 18 to 24 years (AOR=2.30 [95% CI, 1.40 to 3.79]; I², 91%).

“To our knowledge, this study is the first meta-analysis to summarize the evidence to date about the association between ENDS use and marijuana use among youths,” the study authors wrote in their conclusion.

“This study suggests that, in addition to potential harms of using ENDS alone and an increased risk of using other forms of nicotine or tobacco, ENDS use is significantly associated with use of at least 1 other addictive psychoactive substance: marijuana. These findings should be taken into account in the design of public policies aiming to restrict access to ENDS for minors. This study also opens the door to other similar meta-analyses looking at the association between ENDS use and use of alcohol or other drugs.”