New research shows that marijuana users under 50 are six times more likely to have a heart attack than non-users, even if they are otherwise healthy.
The findings are based on two studies led by Dr. Ibrahim Kamel, a clinical instructor at the Boston University Chobanian & Avedisian School of Medicine.
The researchers analyzed health data from over 4.6 million adults under 50 through the TriNetX global health research network. None of the participants had existing heart issues, and their blood pressure, cholesterol levels, and blood sugar were all within healthy ranges. They also had no history of diabetes, tobacco use, or coronary artery disease.
During an average follow-up period of more than three years, cannabis users were found to have a sixfold higher risk of heart attack, double the risk of heart failure, a fourfold higher risk of ischemic stroke, and triple the risk of heart-related death, heart attack, or stroke.
To verify their findings, the researchers reviewed 12 previous studies involving more than 75 million participants from the U.S., Canada, and India. Seven of those studies confirmed a significant link between marijuana use and heart attack risk, while four showed no significant difference, and one indicated a slightly negative association. Combining all the data, researchers determined that active cannabis users were 1.5 times more likely to experience a heart attack than those who abstained.
Dr. Kamel noted that the study had limitations, as it did not account for the quantity and frequency of marijuana use or consider other potential contributing factors. He acknowledged that cannabis consumption is often associated with other substances, such as cocaine or other illicit drugs, which were not factored into the research.
The results raise serious concerns about how marijuana impacts the cardiovascular system. Researchers suggest that cannabis may interfere with heart rhythm regulation, increase the heart’s oxygen demand, and cause blood vessels to struggle to relax and expand, disrupting blood flow.
Cannabis use also appears linked to other health issues, including impaired brain function, mental health disorders, gastrointestinal problems, lung damage, and even cancer. High-THC cannabis products have been connected to more severe cases of cannabis use disorder, a condition where users continue consumption despite negative consequences.
As marijuana becomes more potent and widespread, health concerns are growing. In the 1990s, THC levels ranged from 3.7% to 10%. Today, products commonly feature THC concentrations as high as 18.7%, particularly in states like Colorado.
Despite the health risks, marijuana legalization continues to spread. While the drug remains illegal at the federal level, 39 states and Washington, D.C., have legalized medical use, and 24 states allow recreational use for adults over 21.
These findings are particularly relevant as cannabis use becomes more common than alcohol consumption among young adults. According to the 2023 Cannabis Global Price Index, New Yorkers alone consume over 62 metric tons of marijuana annually, making the city the world’s marijuana consumption capital.
Dr. Kamel stressed the importance of patients being forthcoming with their doctors about cannabis use, just as they would be about cigarette smoking. He pointed out that doctors are their patients’ advocates and having accurate information matters when assessing overall cardiovascular risk.
The researchers are scheduled to present their findings on March 29 at a meeting of the American College of Cardiology in Chicago.