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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.
Previous research had shown marijuana can cause the heart to beat irregularly, a condition that can increase the amount of oxygen needed by the heart, Ladha said. Yet, marijuana can limit the amount of oxygen delivered.
"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)."
The researchers analyzed data from more than 33,000 adults ages 18-44. 17% of the adults surveyed reported using marijuana within the past 30 days, and of them, 1.3% later suffered a heart attack. Of the survey respondents who didn't use the drug, only 0.8% experienced a heart attack.
They found that marijuana users were more likely to be male, smoke cigarettes, vape, and drink alcohol heavily. These factors might also contribute to the participants' heart attack risk, but they were adjusted for in the analysis.
"Physicians and other clinicians need to be aware of this potentially important relationship," David Mazer, MD, study co-author 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."
"There's more and more data raising concern for the negative cardiovascular effects of cannabis, whether it's stroke, arrhythmias or myocardial infarction," says Christine Tompkins, MD, an acting associate professor of cardiology at the Emory School of Medicine in Atlanta, who was not involved in the research. "We need to really get a better understanding of what the risks are associated with cannabis use since it's becoming more widely used," she adds.
Overall, 13.6 percent had reported using marijuana within the that month. Among the results, researchers found that young adults with recent marijuana use had nearly two times higher odds of stroke compared with nonusers. For frequent users, defined as those who used marijuana 10 days or more a month, the risk rose to 2.5 times higher than nonusers. Infrequent users of pot who also smoked cigarettes or e-cigarettes, stroke risk was nearly three times higher when compared with nonusers.
This should serve as a "wake-up call," at least for young heavy cannabis users, says a co-author of the study, Rupak Desai, MBBS, a research fellow in the division of cardiology at the Atlanta VA Medical Center.
Author
Dr. Mark L. Meyer
Dr. Meyer graduated from Haverford College with a Bachelor of Science, High Honors, in cellular and molecular biology, Phi Beta Kappa, Magna Cum Laude. He attended the Yale University School of Medicine, where he also completed a categorical residency in Internal Medicine, served for one year as an Emergency Department attending physician, and held the title of Clinical Instructor in the Department of Surgery. During this time, Dr. Meyer obtained a J.D. from the Yale Law School, concentrating on medical ethics, scientific research law, and FDA law. He then completed a fellowship in Cardiovascular Diseases at the Hospital of the University of Pennsylvania, where he obtained Level 3 Nuclear Cardiology training.
