Young adults who frequently use marijuana twice as likely to have heart attack

A history of myocardial infarction was more frequently reported among young adults who recently used cannabis compared with those who did not use the substance, a cross-sectional study showed.

“Although heavy cannabis use has been reported to trigger acute myocardial infarction, the current evidence is limited to case-control studies that are prone to bias and studies relying solely on administrative data,” researchers wrote in the Canadian Medical Association Journal. “It is also limited in its definition of exposure, as these studies assess patients with heavy cannabis use (cannabis abuse or cannabis use disorder).”

They analyzed data from 33,173 adults aged 18 to 44 years who completed the 2017 and 2018 Behavioral Risk Factor Surveillance System (BRFSS) survey. Of the total, 4,610 said they had used cannabis at least once within the past 30 days. The BRFSS was chosen because it “is the best available source for providing insights which are generalizable and nationally representative," Nikhil Mistry, a PhD candidate at the University of Toronto, said in a press release.

Mistry and colleagues reported that history of MI was more frequent among recent cannabis users (1.3% vs. 0.8%; adjusted OR = 2.07; 95% CI, 1.12-3.82). Those who said they used cannabis more than four times monthly were also more likely to have a history of MI (aOR = 2.31; 95% CI, 1.18-4.5), as were those whose primary method of cannabis use was smoking (aOR = 2.01; 95% CI, 1.02-3.98).

The link remained significant when the data were adjusted for hypertension and hypercholesterolemia (aOR = 3.54; 95% CI, 1.13-11.05), but not for negative control outcomes of skin cancer (aOR = 1.02; 95% CI, 0.59-1.75) and blindness (aOR = 0.98; 95% CI 0.71-1.35), “which suggested limited residual confounding in our model,” the researchers wrote.

“Physicians and other clinicians need to be aware of this potentially important relationship,” David Mazer, MD, study coauthor and a clinician scientist at Unity Health Toronto, said in the press release. “Cannabis use should be considered in cardiovascular risk assessment. When making decisions about cannabis consumption, patients and physicians should consider its associated benefits and risks, in the context of their own health risk factors and behaviors.”