Weed users are much more likely to suffer a heart attack, stroke or other life-threatening heart condition than people who don’t indulge, a new study says.

Adults under 50 are more than six times as likely to suffer a heart attack if they use marijuana, compared to non-users, researchers reported March 18 in the journal JACC Advances.

They also have a dramatically higher risk of stroke, heart failure and heart-related death, researchers said.

“Asking about cannabis use should be part of clinicians’ workup to understand patients’ overall cardiovascular risk, similar to asking about smoking cigarettes,” lead researcher Dr. Ibrahim Kamel, a clinical instructor at the Boston University Chobanian & Avedisian School of Medicine, said in a news release.

Weed is legal for recreational use in 24 states and for medical use in 39 states. 

These results show that it is not inherently harmless, even as it is legalized across the U.S., researchers said.

“At a policy level, a fair warning should be made so that the people who are consuming cannabis know that there are risks,” Kamel said.

For the study, researchers analyzed health records for more than 4.6 million adults younger than 50, comparing the heart health of cannabis users to non-users.

Everyone included in the study had no heart health problems at the outset. 

Their blood pressure and cholesterol levels were within a healthy range, and they had no diabetes, tobacco use or indication of clogged arteries.

During an average follow-up of more than three years, weed users had:

• A more than sixfold increased risk of heart attack compared to non-users.

• Four times the risk of stroke.

• Twice the risk of heart failure.

• Triple the risk of heart-related death, heart attack or stroke.

To double-check these results, researchers performed a follow-up evidence review involving 12 previously published studies with more than 75 million participants.

The pooled data showed that active marijuana users were 1.5 times as likely to suffer a heart attack compared to people not currently using weed.

Researchers are scheduled to present results of the evidence review March 29 at a meeting of the American College of Cardiology in Chicago.

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.

Weed might increase the risk of heart problems by affecting heart rhythm, increasing oxygen demand in the heart muscle, and making it harder for blood vessels to effectively relax and expand, researchers speculated.

But Kamel said there’s a chance that weed users might be taking other substances that also increase their heart health risk.

“We should have some caution in interpreting the findings, in that cannabis consumption is usually associated with other substances such as cocaine or other illicit drugs that are not accounted for,” he said.

Given that, Kamel said patients need to be honest with their doctor about their drug use, including weed.

“Patients should be forthcoming with their doctors and remember that we are their number one advocate and having the full story matters,” he concluded.

More information

The U.S. Centers for Disease Control and Prevention has more on the health effects of cannabis.

SOURCE: American College of Cardiology, news release, March 17, 2025

Source: HealthDay

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