An NIH-funded observational study shows that the risk increases markedly with more frequent use. Frequent smoking of cannabis can significantly increase a person’s risk of heart attack and stroke, according to an observational study supported by the National Institutes of Health. The study, published in the Journal of the American Heart Association , uses data from nearly 435,000 American adults and is among the largest ever explored in the relationship between cannabis and cardiovascular events.
The study, funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the NIH, found that daily cannabis use was associated with a 25% greater chance of having a heart attack and a 42% greater chance of having a heart attack. more likely to have stroke compared to non-use. Less frequent use was also associated with a higher risk of cardiovascular events. Weekly users showed a 3% increase in the likelihood of having a heart attack and a 5% increase in the likelihood of having a stroke.
About 75% of study respondents reported using cannabis primarily by smoking it. About 25% of respondents reported using cannabis through some method other than smoking, such as vaping , drinking, or eating the drug.
"We know that toxins are released when you burn cannabis, similar to those found in tobacco smoke," said corresponding author Abra Jeffers, Ph.D., a data analyst at Massachusetts General Hospital in Boston and former researcher at the Center for Tobacco. Control Research and Education at the University of California, San Francisco, where he conducted the study as part of his postdoctoral work.
"We have long known that tobacco smoking is linked to heart disease, and this study is evidence that cannabis smoking also appears to be a risk factor for cardiovascular disease, which is the leading cause of death in the United States." Jeffers said. "Cannabis use could be an important and underappreciated source of heart disease."
The researchers note that while the exact mechanisms linking cannabis to heart disease are unclear and were not explored in the current study, multiple factors could play a role. In addition to toxins, endocannabinoid receptors (the part of cells responsible for recognizing tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis) are widespread in the body’s cardiovascular tissues and could facilitate cardiac risks.
Cannabis use has increased significantly over the past 20 years across the country as negative perceptions about its use have decreased, according to government surveys on drug use and health. In the United States, cannabis is currently legal in 38 states for medicinal use and 24 states for recreational use. Some studies have linked its regular use to impaired brain development and lung damage, as well as certain cardiovascular diseases. However, there are gaps in knowledge about the adverse effects of cannabis on the heart.
To take a closer look at associations between cannabis use and health, Jeffers and his research team used 2016-2020 data from the Centers for Disease Control and Prevention’s Behavioral Risk Factor Surveillance Survey. The national cross-sectional survey, conducted annually by the CDC, included 434,104 adults ages 18 to 74 from 27 states and 2 U.S. territories. Most respondents were white (60%), while about 12% were white. were black, 19% were Hispanic, and 9% were other race/ethnicity.
The researchers assessed the association between smoking cannabis (the number of days participants reported smoking the drug in the past 30 days) with self-reported cardiovascular outcomes, including coronary heart disease, heart attack, stroke, and a composite measure of the three. They adjusted for participants’ tobacco use and other characteristics, including their age, sex, race, body mass index or BMI, obesity, diabetes, physical activity levels and socioeconomic status.
"This is an important finding for public health, particularly given our continued efforts to reduce the burden of heart disease in this country," said David C. Goff, M.D., Ph.D., director of the NHLBI Division of Cardiovascular Sciences. .
"Asking patients about their cannabis use during routine medical or physical exams in the same way we might ask them about tobacco use will help us learn more about the long-term effect of marijuana on the body," Jeffers said.
Clinical perspective What’s new? Cannabis use is associated with an increased risk of myocardial infarction and stroke, with higher odds of events associated with more days of use per month, controlling for demographic factors and smoking. Similar increases in risk associated with cannabis use are found in smokers who have never smoked tobacco. What are the clinical implications? Patients should be screened for cannabis use and advised to avoid smoking cannabis to reduce the risk of premature cardiovascular disease and cardiac events. |
The study was largely funded by the NHLBI under grant 1R01HL130484-01A1 and included additional support from National Cancer Institute grant T32 CA113710. For a more complete funding disclosure and list of authors, see the full JAHA research article .
