Marijuana consumption, even occasional, increases the risk of cardiovascular events, warns a new study which for the first time separates this risk from that associated with smoking.
This conclusion comes from an analysis of responses provided by some 434,000 participants in a survey conducted by the US Centers for Disease Control and Prevention.
And even if the data are self-reported by the subjects, which inevitably opens the door to a certain bias, the study is interesting because consumers often use both tobacco and marijuana, recalled Doctor François Simard, clinical cardiologist at the Montreal Heart Institute.
“We look at whether they have cardiovascular events in the future, and we notice that yes, the risk is increased,” he said. But we always wonder, is it just because they used cigarettes? And then ultimately, marijuana is just a substance that doesn’t necessarily have a link to all of this? »
Instead, the new analysis shows that any use of cannabis increases the risk of myocardial infarction or stroke, even among users who have never smoked tobacco. The risk increased with the frequency of cannabis use.
“We found that, after controlling for potential confounders, cannabis use had a strong independent effect in the general population and a strong association with cardiovascular events, independent of the effects of tobacco cigarette and e-cigarette use. », Write the authors.
More specifically, daily marijuana use increased the risk of coronary heart disease by 16%, the risk of heart attack by 25%, and the risk of stroke by 42%. The overall risk of cardiovascular events increased by 28%.
“(What’s new with this study is) that it took out people who were concurrently using cigarettes, and it only took people who reported (using) marijuana,” said the Doctor Simard. (The authors) noticed that these people have a higher cardiovascular risk over time. This is one of the first times that this discernment has been made. »
The study, he continues, “adds a sufficient argument to at least tell people, be careful, you should not take (cannabis) lightly, probably that it influences your cardiovascular risk […]. The study raises a flag and says, be careful, this confirms our initial suspicions. »
Cannabis smoke and tobacco smoke closely resemble each other, the study authors point out, and the main difference between the two concerns the substance that causes dependence: THC for the first and nicotine for the second.
“All the other substances that are harmful to the heart, but also to the risk of cancer and everything, are inhaled by patients,” confirmed Dr. Simard.
The study’s data are all the more relevant, according to its authors, as cigarette use is declining while marijuana use is gaining popularity – a trend that is possibly associated with the perception of “banality” that surrounds cannabis.
However, the reality on the ground is very different, warns Doctor Simard.
“I work in the coronary unit and I see patients who have heart attacks, sometimes at a very young age,” he said. We’re trying to dig deeper: what is the risk factor? What could have started all this? Then sometimes, the only thing I notice is that they consume cannabis.
“Of course it’s rather anecdotal, it’s my experience, but I talk to colleagues, and everyone has cases like that. […] It’s a matter of time, I think, before studies clearly demonstrate the link. »
The findings of this study were published by the Journal of the American Heart Association.