New Study Links Marijuana Use in Young Adults to Increased Risk of Heart Attack, Stroke, and Heart Failure

A recent study published in the Journal of the American College of Cardiology (JACC) has raised significant concerns about the cardiovascular health risks associated with marijuana use among young adults. The research indicates that individuals under the age of 50 who consume marijuana are significantly more likely to experience heart attacks, strokes, and heart failure compared to their non-marijuana-using counterparts. This study, analyzing data from over 4.6 million individuals, adds to a growing body of evidence suggesting a potential link between marijuana use and adverse cardiovascular outcomes.

The study found that young marijuana users are approximately 6.2 times more likely to experience a myocardial infarction, commonly known as a heart attack. This is a stark increase in risk, especially considering the study controlled for other common cardiovascular risk factors. Furthermore, the research revealed that young marijuana users are also 4.3 times more likely to experience an ischemic stroke, a condition where blood flow to the brain is blocked, and twice as likely to experience heart failure, a condition where the heart is unable to pump blood effectively to meet the body’s needs.

The researchers meticulously screened participants to exclude those with pre-existing health conditions typically associated with cardiovascular risks, such as hypertension (high blood pressure), coronary artery disease, diabetes, and a prior history of myocardial infarctions. Notably, the study also excluded individuals who use tobacco, eliminating another significant potential confounding factor. This careful methodology strengthens the study’s findings and suggests that marijuana use itself may be a contributing factor to these adverse cardiovascular events.

Ahmed Mahmoud, the lead researcher and a clinical instructor at Boston University, emphasized the need for further investigation despite the seemingly significant numbers. He cautioned that research on marijuana’s effects on the cardiovascular system is still limited, and more data is required to draw definitive conclusions. "Until we have more solid data, I advise users to try to somehow put some regulation in the using of cannabis," Mahmoud stated. He further added, "We are not sure if it’s totally, 100% safe for your heart by any amount or any duration of exposure."

The lack of conclusive research leaves scientists and doctors uncertain about the precise mechanisms by which marijuana might affect the cardiovascular system. However, existing research suggests that marijuana can increase heart rate and blood pressure, both of which can strain the cardiovascular system. The Centers for Disease Control and Prevention (CDC) has also reported on these effects.

Mahmoud proposed a potential mechanism by which marijuana could contribute to cardiovascular problems. He suggested that marijuana might cause minor defects in the lining of the coronary arteries, the blood vessels that supply blood to the heart. "Because cannabis increases the blood pressure and makes the blood run very fast and make some defects in the lining to the coronary arteries, this somehow could make a thrombosis (formation of a blood clot) or a temporary thrombosis in these arteries, which makes a cardiac ischemic (stroke) or the heart muscle is not getting enough oxygen to function," Mahmoud explained. "This is what makes the heart injured and this is a myocardial infarction or heart attack."

Stanton Glantz, a retired professor from the University of California, San Francisco School of Medicine, who co-authored a study on marijuana’s cardiovascular effects published in the Journal of the American Heart Association last year, echoed these concerns. Glantz believes that smoking marijuana has similar effects on the cardiovascular system as smoking tobacco.

The CDC reports that smoking cigarettes introduces harmful chemicals into the bloodstream, which can damage the heart and blood vessels. This damage can lead to a variety of cardiovascular diseases, including coronary heart disease, hypertension, heart attack, stroke, aneurysms, and peripheral artery disease. Cigarette smoke can also alter blood chemistry, promoting the formation of plaque in the arteries, a condition known as atherosclerosis. Plaque buildup narrows the arteries, making it harder for blood to flow and increasing the risk of blood clots, which can lead to heart attacks, strokes, and death.

The newly published study aligns with previous research in the field, reinforcing the potential link between marijuana use and cardiovascular problems. The earlier Journal of the American Heart Association study, which surveyed over 434,000 people aged 18-74, also found that marijuana affects the cardiovascular system, even among users who did not use tobacco. The 2024 study specifically highlighted that individuals who consume marijuana, particularly through inhalation, are more likely to experience coronary heart disease, myocardial infarction, and stroke. "There is a statistically significant increase in risk," Glantz emphasized.

Glantz further clarified the key difference between the new study, co-authored by Mahmoud, and the 2024 study, pointing to the populations examined. The 2024 study utilized data from the Behavioral Risk Factor Surveillance Survey, a CDC-operated telephone survey designed to be representative of the U.S. population. In contrast, the new study analyzed data from 53 healthcare organizations using the TriNetX health research network, which includes information from individuals who have sought medical care.

"Simply put, the CDC survey includes information from what is supposed to be ‘representative’ of the U.S. population, whereas TriNetX includes information from individuals who have visited a healthcare institution," Glantz explained. This distinction is important because it suggests that the new study may capture individuals with more severe or symptomatic cardiovascular issues, potentially leading to a higher observed risk.

The accumulating evidence underscores the need for continued research into the cardiovascular effects of marijuana, particularly as its use becomes increasingly widespread and legalized in many regions. While further studies are necessary to fully understand the underlying mechanisms and long-term consequences, the current findings warrant caution and encourage informed decision-making regarding marijuana consumption, especially among young adults. Healthcare professionals should also be aware of these potential risks and counsel their patients accordingly, emphasizing the importance of moderation and harm reduction strategies until more definitive data becomes available. The seemingly innocuous nature of marijuana use in popular culture should be balanced with a clear understanding of the emerging scientific evidence suggesting potential risks to cardiovascular health.