Stroke and Heart Attack Risk in Heavy Weed Users (Even Those Who Do Not Smoke Tobacco)

A new study published by researchers at Massachusetts General Hospital (MGH) adds to a growing body of evidence supporting a link between marijuana use and heart disease, stroke, and heart attack risk.

According Abra Jeffers, a data scientist at MGH, this study is one of the largest to demonstrate a link between marijuana use and cardiovascular health in individuals who do not also smoke tobacco.

Data from 400,000+ individuals, aged 18 to 74, was gathered from a behavioral risk factor survey conducted by the Centers for Disease Control and Prevention between 2016 and 2020. After analyzing the data, researchers determined that daily users daily had a notably higher risk of heart-related issues, including:

• Heart Attack (49% higher risk): A sudden blockage of blood flow to the heart muscle.
• Stroke (116% higher risk): A disruption of blood flow to the brain.

Investigators found that even occasional weed use (between 0 and 30 days per month) was associated with increased heart risks. The relationship between weed use and cardiovascular outcomes remained consistent for men under 55 and women under 65.

This research adds to growing body of evidence supported by other researchers.

A 2021 study published in the journal Circulation found that the number of heart attack patients under the age of 50 who were regular weed users (those with a diagnosis of cannabis use disorder) nearly tripled from 2007 to 2018. In 2007, only 2.4% of heart attack patients aged 18 to 49 had a history of regular weed use. In 2018, that proportion had grown to 6.7% (Desai, Circulation, 2021).

The reason behind the correlation is not known, but marijuana use can lead to a rise in heart rate, increased blood pressure, and may also trigger atrial fibrillation in some individuals. Collectively, these side effects could put a minority of users at increased risk of heart attack (Banerjee, Cureus, 2020).

Importantly, studies examining the link between weed use and heart health are observational. This means the researchers look at trends from reported information, which differs from controlled trials. The major limitation of an observational study is that it cannot show cause and effect, only correlation.

So, doctors know that people who smoke weed have heart attacks more frequently than the general population. But they don’t know why. Is it because they smoked weed regularly? Or are there other factors that weren’t accounted for in the reported data. A controlled trial would be better able to determine that relationship.

That being said, the strength of association between heavy marijuana use and heart attack risk may be much stronger than suggested. That’s because there are actually quite a few studies that have shown similar findings.

• A 2020 study found that even first-time marijuana users may be at greater risk for heart attack (Banerjee, Cureus, 2020).
• Another recent study found that regular weed use was associated with heart attack in young people with no other risk factors (Patel, Trends Cardiovasc Med, 2020).
• A 2013 study found weed users were at greater risk for cardiovascular diseases, including heart attack, stroke, and damaged blood vessels (Desbois, Ann Vasc Surg, 2013).
• A 2019 meta-analysis (a study that compiles and analyzes the results from many other studies) concluded that marijuana use puts young people at risk for cardiovascular disease (Richards, Clin Toxicol (Phila), 2019).

This research is important because perceptions of marijuana risks are on the decline. In 2015, only 32% of high school seniors thought marijuana use was risky compared to 47% of seniors in 2010, and 79% in 1991 (Weiss, Int J Drug Policy, 2017). While much recent research has been quick to highlight the benefits of using marijuana, like any drug, there are also side effects – just think about prescription drug advertisements and the laundry list of side effects they include!