What is being called the first study to consider specific risk indicators for cardiovascular disease (CVD) in young, healthy cannabis users has found that consuming weed when young may increase the risk of later developing heart disease.

So suggests a new study, published in the Journal of Applied Physiology, out of the University of Guelph (U of G). Investigators explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants.

Researchers “found subtle, but potentially important changes in heart and artery function,” notes a statement from the University of Guelph. “Young, healthy and cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness,” adds the study.

Using ultrasound imaging on all subjects, investigators measured arterial stiffness and arterial function, namely the ability of arteries to appropriately expand with greater blood flow, which are indicators of cardiovascular function and potential disease risk.

The findings indicated arterial stiffness was greater and cardiac function was lower in  consumers compared to non-users.

Christian Cheung is the lead author of the study and a Ph.D. student in the university’s Human Performance and Health Research Lab. / PHOTO BY UNIVERSITY OF GUELPH

The team was surprised to see no difference in artery dilation in response to changing blood flow, notes Christian Cheung, lead author of the study and a Ph.D. student in the university’s Human Performance and Health Research Lab.

Pointing out that cigarette-smokers normally experience stiffer arteries and lower vascular and heart function, “we don’t yet know why in cannabis users there’s no difference in vascular function,” Cheung reports in the statement.

He did note, though, that the differences may reflect variations in how tobacco and cannabis are consumed, the amounts consumed, the frequency of consumption and the user’s age.

“Collectively, these findings suggest there exist sub-clinical differences in cardiovascular physiology in cannabis users, which may be indicative of greater risk of the development of future CVD,” the study states.

“In the cigarette literature, heavy, long-term smokers show reduced vascular function, but that’s not necessarily the case for younger smokers,” Cheung points out.

“We don’t yet know why in cannabis users there’s no difference in vascular function.” / PHOTO BY ISTOCK / GETTY IMAGES PLUS

“This is exciting new data, suggesting that even before more overt signs and symptoms of cardiovascular disease are present, there may be more subtle indications in altered physiological function,” says Jamie Burr, a study co-author and a professor in the Department of Human Health and Nutritional Sciences.

As use of cannabis increases worldwide — the second most commonly used substance after alcohol — there is still plenty to learn about the long-term CVD risks associated with smoking weed.

“This is an exciting field of research given the ubiquity of cannabis use and the knowledge gap that exists, it’s a field ripe with opportunity,” notes Cheung.

Members of the research team plan further studies. “Future work should prospectively explore causal links between cannabis smoking and altered cardiovascular function, with a goal of characterizing the relationship between cannabis use and the development of CVD,” the study notes.

Findings from studies to date regarding cannabis use and heart health seem to be all over the place.

A study published in 2016 found that “cannabis use is associated with an acceleration of the cardiovascular age,” adding that “this likely underlies and bi-directionally interacts with its diverse toxicological profile and is of considerable public health and regulatory importance.”

“This is exciting new data, suggesting that even before more overt signs and symptoms of cardiovascular disease are present, there may be more subtle indications in altered physiological function.” / PHOTO BY UNIVERSITY OF GUELPH

The American Heart Association noted in a scientific statement last year that “cannabis may have therapeutic benefits, but few are cardiovascular in nature.”

That sentiment was reflected in another study published last year. Researchers concluded that the effects of cannabis on the cardiovascular system “are extremely worrisome and likely need more attention due to the growing legalization of cannabis for medicinal and recreational use across the U.S.”

But research published in Addiction last summer found that occasional current and lifetime cumulative use of cannabis are not associated with increases in heart abnormalities at middle age.

And another study released this year indicates there appears to be no increased association between cumulative cannabis use and subclinical atherosclerosis, or hardening of the arteries.