Marijuana Use Linked to Higher Heart Attack, Stroke Risks

Cannabis and cardiovascular risks

For the latest study, researchers analyzed national survey data for more than 430,000 adults from 2016 through 2020 to examine an association between cannabis use and cardiovascular outcomes. They found a link between cannabis use and heart disease, heart attack and stroke, and noted that the risk for these events increased with more frequent use.

Daily cannabis users, for example, had 25 percent higher odds of heart attack and 42 percent higher odds of stroke than nonusers. Only 4 percent of study participants who said they used cannabis identified themselves as daily users.

Weekly cannabis users showed a 5 percent increased risk of stroke and a 3 percent increased risk of heart attack.

The researchers also examined the effects for people who had never smoked or vaped tobacco and found that just using cannabis was associated with several heart risks.  

The majority of cannabis users in the study reported smoking it over other forms of consumption. According to the Centers for Disease Control and Prevention (CDC), marijuana smoke delivers many of the same substances researchers have found in tobacco smoke, and these substances are harmful to the cardiovascular system.

“Cannabis smoke is not all that different from tobacco smoke, except for the psychoactive drug: THC (tetrahydrocannabinol) vs. nicotine,” first study author Abra Jeffers, a data analyst at Massachusetts General Hospital in Boston, said in a statement. “Our study shows that smoking cannabis has significant cardiovascular risk, just like smoking tobacco. This is particularly important because cannabis use is increasing, and conventional tobacco use is decreasing.”

Cannabis can also make the heart beat faster and increase blood pressure immediately after use, the CDC says. What’s more, the part of cells that are responsible for recognizing THC — called endocannabinoid receptors — are widespread in the body’s cardiovascular tissues “and might facilitate heart risks,” a news release from the National Institutes of Health (NIH) says. The study was funded by the National Heart, Lung, and Blood Institute, part of NIH. 

“The cannabis plant has hundreds of compounds, many of which interact with our body’s physiological functions in ways we don’t completely understand yet,” Sera says.  

Have the cannabis conversation

Robert Page, a professor of clinical pharmacy with the Skaggs School of Pharmacy and Pharmaceutical Sciences at the University of Colorado School of Medicine, says the study findings should be a call to action for all health care providers, as it “adds to the growing literature that cannabis use and cardiovascular disease may be a potentially hazardous combination.”

Page says that as legal access to cannabis continues to expand across the U.S., “practitioners and clinicians need to remember to assess cannabis use at each patient encounter in order to have a nonjudgmental, shared decision conversation about potential cardiovascular risks and ways to reduce those risks.”

“It can be a challenging discussion to have with patients because there is evidence that cannabis has some therapeutic properties. However, as suggested by this study, cannabis use also has significant cardiovascular risks,” Salomeh Keyhani, M.D., professor of medicine at the University of California, San Francisco and an author on the study, said in a statement.

Sera says patients should also be bringing up any questions or concerns surrounding cannabis use with their doctors and pharmacists. The stigma is lessening in the medical community, she says, and “the reality is that not everyone is a good candidate for medical cannabis.”

For example, there are some medications that can interact with cannabis, including some cholesterol drugs and blood thinners, Page says, so it’s important to ask your health care provider if any drugs you are taking can have negative effects when mixed with marijuana.

This is especially key for older adults, Page adds, since “we know older adults take an increasing number of medications.”

Patients should also ask if they have any medical conditions that might increase the risk of serious side effects from cannabis, Sera says.