People who regularly smoke medical marijuana may be increasing their risk for a heart attack, heart failure or stroke, new research suggests.

One study found that cannabis use among older patients increases the risk of heart attack or stroke by 20%. The second study found that using cannabis increased the risk of heart failure by 34%.

The studies are scheduled for presentation at an upcoming meeting of the American Heart Association (AHA), in Philadelphia. Research presented at meetings should be considered preliminary until published in a peer-reviewed journal.

“Patients and physicians should be mindful about these events as we have seen that more patients are being started on marijuana,” said Dr. Avilash Mondal, an internist at Nazareth Hospital in Philadelphia and lead researcher of the first study.

In that study, Mondal’s team looked at nearly 29,000 marijuana users over 65 years of age who were part of a nationwide database of inpatient hospital stays. None smoked traditional tobacco cigarettes.

Of that population, 14% suffered a heart attack or stroke.

Those with cannabis use disorder who suffered a heart attack or stroke were more likely to be Black patients, with AIDS, alcohol or drug abuse, depression or high blood pressure, the study found. 

This study doesn’t prove that marijuana causes heart attacks or stroke, only that there appears to be an association, Mondal said.

He suspects, however, that smoking marijuana may have the same effects as cigarette smoking, including an increased risk of major heart events.

The second study was led by Dr. Yakubu Bene-Alhasan from Medstar Health in Baltimore. 

From data on 157,000 marijuana users, his team found that over four years of follow-up, nearly 2% developed heart failure. People who used cannabis daily had a 34% increased risk compared with those who never used it.

This risk was the same regardless of age, sex or smoking history. 

When coronary artery disease was taken into account, the risk of heart failure dropped from 34% to 27%, suggesting that coronary artery disease may be the pathway from marijuana use to heart failure.

“Our results should encourage more researchers to study the use of marijuana to better understand its health implications, especially on cardiovascular risk,” Bene-Alhasan said in a written statement.

Whether marijuana actually causes cardiovascular problems is still up in the air, according to Paul Armentano, deputy director of NORML, which advocates for the legalization of marijuana.

Armentano noted that a study published in the October issue of the journal Circulation found no increased risk of heart issues among marijuana users. Other studies have also failed to show an association between the drug and cardiovascular events, he said.

“My presumption is it’s the association with other unhealthy behaviors rather than cannabis use per se that is driving the association highlighted in these latest AHA papers,” he explained.

It is well known that inhaling cannabis by a vaporizer significantly mitigates exposure to combustion, and the use of herbal cannabis vaporizers has been determined to be safe and effective, Armentano said. 

“Of course, legal cannabis markets also now offer a variety of non-inhalable formulations of cannabis-infused products as well,” he added.

One expert said that other studies, however, have linked marijuana to heart attacks and strokes, and though how the drug contributes to these problems isn’t known, people should be aware of the potential dangers.

“Marijuana use has been associated with an increased risk of cardiovascular events in prior studies,” said Dr. Gregg Fonarow, director of the Ahmanson-UCLA Cardiomyopathy Center in Los Angeles.

“Further studies are needed to validate these findings and further explore potential mechanisms,” Fonarow added. “Individuals should be aware of the emerging evidence regarding marijuana use and different types of cardiovascular risk.”

More information

For more on the harms of marijuana, head to the U.S. Substance Abuse and Mental Health Services Administration.

SOURCES: Avilash Mondal, MD, internist, Nazareth Hospital, Philadelphia; Paul Armentano, deputy director, NORML, Washington, D.C.; Gregg Fonarow, MD, director, Ahmanson-UCLA Cardiomyopathy Center, Los Angeles; American Heart Association, news release, Nov. 6, 2023; presentation, American Heart Association meeting, Philadelphia, Nov. 11, 2023

Source: HealthDay