Marijuana is now legal in many places, but is it safe? Two new studies add to mounting evidence that people who use cannabis are more likely to suffer a heart attack than people who do not use the drug, even among younger and otherwise healthy adults. The findings are from a retrospective study of over 4.6 million people published in JACC Advances and a meta-analysis of 12 previously published studies being presented at the American College of Cardiology’s Annual Scientific Session (ACC.25).
Marijuana use has risen in the United States, especially in states where it is legal to buy, sell and use the drug recreationally. In the retrospective study, researchers found that cannabis users younger than age 50 were over six times as likely to suffer a heart attack compared to non-users. The meta-analysis, which is the largest pooled study to date examining heart attacks and cannabis use, showed a 50% increased risk among those who used the drug.
Kamel and his team conducted the retrospective study using data from TriNetX, a global health research network that provides access to electronic medical records. Their findings indicate that over an average follow-up of over three years, cannabis users had more than a sixfold increased risk of heart attack, fourfold increased risk of ischemic stroke, twofold increased risk of heart failure and threefold increased risk of cardiovascular death, heart attack or stroke. All study participants were younger than age 50 and free of significant cardiovascular comorbidities at baseline, with blood pressure and low-density lipoprotein (LDL) cholesterol levels within a healthy range and no diabetes, tobacco use or prior coronary artery disease.
For the meta-analysis, the researchers pooled data from 12 previously published research studies that collectively included over 75 million people. The studies were rated as being of moderate to good quality in terms of methodology. Of the 12 studies, 10 were conducted in the United States, one in Canada and one in India. Some of the studies did not include information about participants’ ages, but the average age was 41 years among those that did, suggesting that the pooled sample reflected a relatively young population.
Taken individually, seven of the studies found a significant positive association between cannabis use and heart attack incidence, while four showed no significant difference and one showed a slightly negative association. When the researchers pooled the data from all studies and analyzed it together, they found a significant positive association, with active cannabis users being 1.5 times as likely to suffer a heart attack compared with those who aren’t current users.
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