It’s well known that smoking cigarettes takes a toll on the heart, and now a large study in the Journal of the American Heart Association suggests the same may be true of marijuana.
The study, of close to 435,000 U.S. adults, found that those who used marijuana every day—mostly smoking it—were more likely than non-users overall to have a history of heart disease or stroke. And although many also smoked cigarettes, that did not explain the findings: Even among lifelong nonsmokers, daily marijuana use was linked to cardiovascular trouble.
The findings come at a time when marijuana use is rising among Americans—as legalization grows and negative perceptions of the drug decline. When it comes to the risks of heart disease and stroke, specifically, some researchers have questioned whether marijuana has any ill effects beyond those from tobacco use.
The researchers attempted to dig into that issue, using data from a large national health survey of Americans ages 18 to 74. Of adults surveyed between 2016 and 2020, 11 percent said they had used marijuana in the past month, including 4 percent who had used it daily. For most people (about three-quarters), smoking the drug was their method of choice.
Overall, marijuana users were more likely than non-users to have ever suffered a heart attack or stroke. The odds rose in tandem with the frequency of use (number of days per month), with the highest risks seen among daily users: Compared with people who did not use marijuana, they had a 25 percent and 42 percent greater risk of heart attack and stroke, respectively.
Relatively few people vaped the drug or consumed edibles regularly, and the study did not separately analyze their potential effects on heart disease or stroke risk compared to smoking marijuana.
Not surprisingly, marijuana users did have higher rates of cigarette smoking than non-users (as well as daily alcohol consumption). But the researchers accounted for those differences in their analysis. Plus, the link between marijuana and cardiovascular disease was even stronger among those who said they had never smoked cigarettes. In that group, daily marijuana users had a 49 percent greater risk of heart attack, and twice the risk of stroke, compared to non-users.
As an observational study, it can’t say why marijuana users faced those heightened risks. But, as the researchers point out, marijuana smoke contains many of the same toxins as cigarette smoke, which could gradually damage blood vessels feeding the heart and brain. Meanwhile, THC (the active ingredient in marijuana) has short-term effects on the cardiovascular system—raising heart rate and blood pressure, for instance. So there’s the potential for precipitating a heart attack or stroke in some people, the researchers note.
That latter fact suggests that vaping or ingesting marijuana may not be benign, either, when it comes to cardiovascular disease. More research is needed, however, to fully understand these health risks.
In the meantime, we know those smoking alternatives carry their own risks, such as intoxication and THC poisoning—including many reported cases of children and pets ingesting edibles with serious consequences. So if you do use marijuana in any form, remember that despite today’s changing attitudes, it’s still a drug. Judicious use—along with safe storage—is essential.
