Study Links Chronic Cannabis Use to Cardiovascular Issues
A recent study has uncovered a concerning association between long-term cannabis use and a heightened risk of cardiovascular disease, irrespective of whether individuals smoke it or consume edibles. This finding contradicts widely held assumptions about tetrahydrocannabinol (THC), which many perceive as relatively safe, particularly when it’s ingested.
The research, published on May 28 in the journal JAMA Cardiology, indicated that those who smoke THC experience notably worse artery function compared to non-users. Edible consumers also exhibited reduced vascular function, though not as severely. In both cases, the study revealed that vascular function dropped to about half of that observed in individuals who do not use cannabis, as stated by the University of California, San Francisco.
Co-author Matt Springer, a cardiovascular researcher at UCSF, commented on how these THC findings could complicate public health messaging surrounding cannabis usage, expressing surprise when he first reviewed the data with lead author and UCSF physician-scientist Leila Mohammadi.
This research adds to an accumulating body of evidence suggesting that long-term cannabis use may lead to cardiovascular harm, including events like heart attacks and strokes, although experts are still debating the exact implications. A earlier study reported an increase in heart attack risk by 25% and a stroke risk by 42% among daily cannabis users compared to non-users.
In this latest study, researchers looked into cannabis’s impact on vascular function by focusing on a group of 55 healthy adults aged 18 to 50 who did not use nicotine and were not regularly exposed to secondhand smoke.
Participants were divided into three groups: marijuana smokers, edible users, and non-users. Those in the cannabis-using categories reported consuming the drug at least three times a week through either smoking or edibles.
To evaluate vascular function, the researchers measured how well the brachial artery in the upper arm could dilate in response to increased blood flow. This involved temporarily blocking blood flow to the artery with an inflatable cuff and then using ultrasound to measure its diameter before and after the cuff was inflated.
Springer remarked that the test provides a “window into the future,” indicating that impaired blood vessel dilation elevates the risk of heart attacks and other adverse cardiovascular events.
Participants who abstained from cannabis had an average dilation of 10.4% of the vessel, significantly higher than the 6.0% observed in smokers and 4.6% in edible users. Typically, healthy individuals experience dilation ranging from 8.0% to 15%. In a prior study, Springer’s lab reported similarly decreased dilation levels among users of e-cigarettes and cigarettes.
To delve deeper into THC’s effects, researchers tested how endothelial cells—lining blood vessels and producing nitric oxide for dilation—reacted to participants’ blood samples. They found that blood from chronic cannabis smokers reduced nitric oxide production in the cells, which likely accounts for their diminished vascular dilation. However, this effect was not seen in edible consumers, suggesting that the mechanism affecting arterial function may differ depending on the method of consumption. More research will be needed to clarify this point, and future studies should aim to replicate these findings in a larger population.
Recent trends indicate that cannabis use among U.S. adults has surged, according to the National Institute on Drug Abuse. Given this rise, understanding the health implications of THC usage is critical, especially as new evidence surfaces that challenges the notion of cannabis as a harmless substance.
