Healthy people who regularly smoked marijuana or consumed THC-laced edibles showed signs of early cardiovascular disease similar to tobacco smokers, a new small study found.
“To my knowledge, it’s the first study looking at THC’s impact on vascular function in humans,” said senior study author Matthew Springer, professor of medicine at the University of California, San Francisco.
“We’re looking at a window in the future, showing the early changes that may explain why smoking marijuana has been linked to later heart disease,” Springer said. “It appears the act of smoking and the THC itself both contribute to those changes in different ways.”
Tetrahydrocannabinol, or THC, is the component of marijuana that provides a high. Prior research on mice found damage to blood vessels that supply oxygen to vital organs after exposure to marijuana smoke, Springer said. Whether marijuana smoke would impact the human vascular system, however, was unknown.
“We found that vascular function was reduced by 42% in marijuana smokers and by 56% in THC-edible users compared to nonusers,” lead study author Dr. Leila Mohammadi, an assistant researcher in cardiology at the University of California, San Francisco, said in an email.
The research only shows an association, Springer said. “We can only state that the cannabis users have poor vascular function, not that cannabis use causes poor vascular function,” he said via email.
The findings on THC-laced edibles was surprising, said Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver.
“Could it be that other forms of marijuana — teas, tinctures, edibles — are perhaps not as benign as we once thought?” said Freeman, who was not involved in the study. “We need larger studies to make a better conclusion about this finding.”
Risk of damaged blood vessels
A single layer of endothelial cells lines all of the body’s blood vessels. When functioning properly, these specialized cells release chemicals such as nitric oxide that control the relaxing and contracting of the canal, thus regulating blood flow. Healthy endothelium cells also play a role in local cell growth and help prevent blood clotting.
When endothelial cells are inflamed, plaque buildup can increase in arteries over time, potentially causing heart attacks, strokes and heart failure. Damage to small blood vessels can also cause kidney and lung disease, comas, delirium, and dementia.
The study, however, did not measure plaque, so the findings do not mean that blood vessels were currently blocked, Springer said.
“The vessels just don’t grow in diameter in real time when they need to pass more blood, indicating an unhealthy vessel wall that presages later cardiovascular disease,” he said.
Prior studies have found strong links between marijuana use and later cardiovascular disease. A February 2024 study found smoking, vaping or eating marijuana led to a significantly higher risk of heart attack and stroke, even if a person had no existing heart conditions and did not smoke or vape tobacco.
Stroke risk rose 42% and the risk of heart attack rose 25% if cannabis was used daily, and risk climbed as the number of days of use of marijuana rose, the study found.
Read More Here: https://www.cnn.com/2025/05/28/health/marijuana-edibles-heart-damage-wellness