Study links cannabis to heart attacks in young adults but research 'can't be used to show a direct cause'

The observational study did not account for the the use of tobacco, alcohol, cocaine or other lifestyle factors.

Sam Riches 3 minute read November 15, 2021

A 2018 peer-reviewed study published in PLOS One found that past cannabis use was actually associated with decreased in-hospital mortality among heart attack patients. ipopba / iStock / Getty Images Plus

Findings presented at the American Heart Association’s virtual Scientific Sessions conference last week revealed a troubling trend.

Researchers found that a growing number of people under 50 diagnosed with cannabis use disorder were later hospitalized for a heart attack, reports Medical Xpress.

And though the findings have yet to be published in a peer-reviewed journal, that hasn’t slowed the rush of headlines linking cannabis use directly to heart attacks. Here’s what you need to know.

To inform their findings, researchers analyzed the medical records of 819,354 people from a large public database of hospital stays and identified people aged 18 to 49 that had been hospitalized for a heart attack and had a previous diagnosis of cannabis use disorder.

They found that, overall, 4.1 per cent of patients hospitalized for heart attacks also had cannabis use disorder, with the trend increasing in recent years. Medical Xpress notes, however, that since the study is “observational and didn’t control for use of other substances such as tobacco, alcohol or cocaine, the research can’t be used to show a direct cause.”

The findings also didn’t account for diet or exercise. A 2018 peer-reviewed study published in PLOS One found that past cannabis use was actually associated with decreased in-hospital mortality among heart attack patients.

The study, conducted by the University of Colorado School of Medicine, Division of Cardiology researchers, analyzed the hospital stays of more than 3,800 heart-attack patients who previously acknowledged consuming cannabis or had tested positive for it.

Researchers also found that the average length of stay for cannabis users (4.51 days) was shorter than non-cannabis users (6.25 days).

Cannabis users also had “a lower incidence of hypertension, heart failure, coronary artery disease, diabetes, and atrial fibrillation.”

In an interview with CBS New York, Dr. Alexandra Straytner said the findings presented at the virtual conference don’t “necessarily mean that cannabis use or cannabis use disorder causes cardiovascular incidents such as heart attacks.

“It may. It could also mean that there are other factors associated with cannabis use that increased risk for heart attack,” she added.

The bottom line is that more research is needed before any firm conclusions can be drawn. The good news is that as more jurisdictions legalize cannabis, it gets easier to perform that research.

In a blog earlier this year, the National Organization for the Reform of Marijuana Laws (NORML) noted that its

Clinical Applications For Cannabis & Cannabinoids now contains 450 peer-reviewed studies assessing the safety and efficacy of whole-plant cannabis and individual cannabinoids.

The post also highlighted that 2020 was a banner year for cannabis research, with more than 3,500 scientific papers published on the subject. Per the National Library of Medicine, the world’s largest medical library, another 3,700 papers have been published so far this year.

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