Marijuana Use May Increase Risk of Heart Attack and Stroke, Review of 16 Studies Suggests

Marijuana use was associated with an increased likelihood of heart attack within 24 hours in 2 studies and stroke in 6 studies. Results also suggested increased risk for angina and acute coronary syndrome, particularly among people with a history of cardiovascular events.

Systematic review searching six databases from 1970 to 2018. Of 3,916 citations, 16 met inclusion criteria. Included 4 cohort studies, 8 case-control studies, 1 case-crossover study, 2 RCTs, and 1 descriptive study. Study sizes ranged from 10 participants to over 118 million hospitalizations.

As marijuana use increases and perceived risk decreases, understanding cardiovascular effects becomes more important. The association with acute events like heart attack and stroke within hours of use suggests a time-sensitive physiological mechanism.

Cardiovascular risk from cannabis use is less studied than respiratory or cognitive effects. As the population of cannabis users ages and more people use cannabis while managing existing heart conditions, these associations become increasingly relevant to public health.

Most studies were observational, limiting causal conclusions. Cannabis use was measured differently across studies (self-report, diagnostic codes, drug tests). Potential confounding by tobacco co-use was not always controlled. Search ended in 2018, missing more recent studies.