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Cannabis use associated with higher risk of heart attack and stroke, study finds

New study on marijuana use and heart risks
New study links marijuana use to increased risk of heart attack and stroke 04:11

Cannabis use  — whether smoked, eaten or vaporized — is associated with a higher number of adverse cardiovascular outcomes, according to a new study.

Published Wednesday in the Journal of the American Heart Association, the research found that risk of coronary heart disease, heart attack and stroke increased with any kind of cannabis use, with heavier use associated with higher odds of negative outcomes.

For daily cannabis users, for example, odds of a heart attack were 25% higher compared to non-users and 42% higher for stroke, the study found. 

"Despite common use, little is known about the risks of cannabis use and, in particular, the cardiovascular disease risks," lead author Abra Jeffers, a data analyst at Massachusetts General Hospital in Boston, said in a news release. "The perceptions of the harmfulness of smoking cannabis are decreasing, and people have not considered cannabis use dangerous to their health. However, previous research suggested that cannabis could be associated with cardiovascular disease. In addition, smoking cannabis — the predominant method of use — may pose additional risks because particulate matter is inhaled."

The cross‐sectional study used survey data from 430,000 adults in the U.S. spanning from 2016 to 2020, with participants aged 18 to 74. The data also allowed them to control for other cardiovascular risk factors and tobacco use, showing a similar association was true even among never‐tobacco smokers.

"Our sample was large enough that we could investigate the association of cannabis use with cardiovascular outcomes among adults who had never used tobacco cigarettes or e-cigarettes," Jeffers said. "Cannabis smoke is not all that different from tobacco smoke, except for the psychoactive drug: THC vs. nicotine. Our study shows that smoking cannabis has significant cardiovascular risks, just like smoking tobacco. This is particularly important because cannabis use is increasing, and conventional tobacco use is decreasing."

Appearing on "CBS Mornings" Thursday, Dr. Céline Gounder, a CBS News medical contributor and editor-at-large for public health at KFF Health News, said she wasn't surprised by the findings.

"Smoke is smoke is smoke. So if you're smoking cigarettes, if you're smoking cannabis, if it's wildfire smoke — people think these things are natural, but smoke is still inhaled. You're inhaling these particles, these other chemicals which can cause damage to your lungs and your heart," she said. 

Even if you're not smoking, other modes of consumption also have health impacts, Gounder said. 

"(With) vaping you're still heating up, not just the THC itself, but all these other chemicals that are in the vaping fluids — additives, flavorings, etc. So when those get heated up, you have these byproducts that are released, which can also be damaging to the lungs and the heart," Gounder says. "In the case of edibles, you have THC. THC alone, whether you smoke it, you vape it, you eat it, THC alone also has effects on the cardiovascular system, which can lead to an increased risk of heart attack and stroke."

If you use cannabis for medicinal purposes, Gounder calls it a "trade-off."

"Any medication, there are risks and benefits, and it really depends on the setting," she says. "If you're talking about somebody who has cancer, the risks and benefits are going to weigh differently from somebody who's a young healthy person who hasn't even turned 18. It really depends on the context."

Since this study did have some limitations, including heart conditions and cannabis use being self-reported, researchers are calling for more research that follow groups of individuals over time to better understand the health implications of marijuana use.

For now, the study "adds to the growing literature that cannabis use and cardiovascular disease may be a potentially hazardous combination," Robert L. Page, professor at the Skaggs School of Pharmacy and Pharmaceutical Sciences at the University of Colorado School of Medicine, said in the release.

The findings should also be a "call to action for all practitioners," added Page, who was not involved in the study.

As cigarette smoking and lung cancer rates have declined, Gounder says the concern now is if cannabis popularity will reverse those trends.

"What's concerning now is will we see lung cancer rates and other issues like heart attack and stroke go up again, as we see use of cannabis go up," she says. 

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