Nonmedical Marijuana Use and Cardiovascular Events: A Systematic Review

Abstract

Introduction: Although marijuana use has increased since 2012, the perceived risk of adverse outcomes has decreased. This systematic review summarizes articles that examined the association between nonmedical marijuana use (ie, observed smoking, self-report, or urinalysis) and cardiovascular events in observational or experimental studies of adults aged ≥18. Methods: We searched Medline, EMBASE, PsycInfo, CINAHL, Cochrane Library Database, and Global Health from January 1, 1970, through August 31, 2018. Of 3916 citations, 16 articles fit the following criteria: (1) included adults aged ≥18; (2) included marijuana/cannabis use that is self-reported smoked, present in diagnostic coding, or indicated through a positive diagnostic test; (3) compared nonuse of cannabis; (4) examined events related to myocardial infarction, angina, acute coronary syndrome, and/or stroke; (5) published in English; and (6) had observational or experimental designs. Results: Of the 16 studies, 4 were cohort studies, 8 were case-control studies, 1 was a case-crossover study, 2 were randomized controlled trials, and 1 was a descriptive study. Studies ranged from 10 participants to 118 659 619 hospitalizations. Marijuana use was associated with an increased likelihood of myocardial infarction within 24 hours in 2 studies and stroke in 6 studies. Results of studies suggested an increased risk for angina and acute coronary syndrome, especially among people with a history of a cardiovascular event. Conclusion: This review suggests that people who use marijuana may be at increased risk for cardiovascular events. As states expand new laws permitting marijuana use, it will be important to monitor the effect of marijuana use on cardiovascular disease outcomes, perhaps through the inclusion of data on nonmedical marijuana use in diverse national and local surveillance systems.