Smoking Weed Could Hurt Your Heart, But We Should Take These Findings With A Grain Of Salt

New research from France has suggested a link between marijuana and cardiovascular disease. Drawing on data from between 2006 to 2010, the researchers found that out of 1,979 marijuana-related reports to the French anti-drug abuse system Addictovigilance, 35 specifically cited complications of the heart. The incidence of such reports tripled in frequency from the start of the period to the end, from 1.1 percent to 3.6 percent – but we shouldn't jump to conclusions just yet.

That marijuana has an effect on the cardiovascular system isn't in and of itself very new news. Running contrary to its reputation as a drug that slows reaction and enables mellow-ness, it also functions as a physical stimulant, accelerating the heart rate somewhat within minutes of use. According to researcher Émilie Jouanjus of France's Centre Hospitalier Universitaire de Toulouse, who spoke to HuffPost, this generally hadn't been thought to be a majorly dangerous or serious issue by medical authorities, but the study has raised some curious and worthwhile questions.

It is not possible to tell whether it is because marijuana-related cardiovascular problems are actually sparse or because it is on the contrary undetected and rather under-reported, in which case we would be facing a major public health problem.

It's also the case, as should always be remembered for stories like this, correlation and causation aren't equivalents. A deeper dig into the study's findings make it harder to say for certain how many of those 35 people actually suffered their heart issues because of marijuana; and whether there's a distinction between the health effects of smoking the drug and, say, eating a marijuana-infused cracker.

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For 16 of the patients, marijuana was a daily vice, while eight reported at least one use in the previous 30 days, and six reported from one-to-nine uses over a 12-month period. The crucial question of the effect of long-term use, as well, is unclear in the data — only five of the reports gave researchers information about the duration of the patient's marijuana history, those ranging from two to 25 years.

Nine of the patients were found to have a personal cardiovascular record, things like high blood pressure and arterial issues, while seven more had family histories. Perhaps the most complicating effect on the findings, however — 21 of the patients were also tobacco smokers, an aggressively unhealthy habit that's links to heart disease and premature death are far better researched and understood than marijuana.

Researchers also had only limited access to patient's body mass indexes, meaning the effect of obesity, one of the most prevalent risk factors for heart disease, was similarly unclear.

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In short, it's not definitive science that pot users need to start worrying about their hearts, but it does beg for more research. As the researchers noted, considering about 1.2 million French citizens are believed to be users, the relative number of incidents reported is extremely miniscule. But that doesn't mean the actual rate of complications is negligible — because people tend to underreport:

The reporting rate of adverse drug reactions is estimated to be 5% in the field of pharmacovigilance. In other words, 95% of cases are usually not captured.