Using cannabis when young may increase the risk of developing heart disease later, according to a study from the University of Guelph in Canada, published in the Journal of Applied Physiology.
In the first study to look at specific risk indicators for cardiovascular disease (CVD) in young, healthy cannabis users, researchers found subtle but potentially important changes in heart and artery function, the University of Guelph reported on 12 April 2021.
Cigarette smoking is known to affect cardiovascular health, causing changes to blood vessels and the heart. Less is known about the impact of smoking cannabis on long-term CVD risk, even as use of the substance grows in Canada and abroad.
Cannabis is the most commonly used recreational substance worldwide after alcohol.
“Cannabis is really widely used as a recreational substance all around the world and is becoming increasingly so,” said Dr Christian Cheung, a postgraduate student in the Human Performance and Health Research Lab, part of Department of Human Health and Nutritional Sciences. “Scientists haven’t done that research with cannabis.”
Cheung’s co-authors were Dr Jamie Burr and Dr Philip Millar, both professors in HHNS, and PhD student Alexandra Coates.
The team studied 35 subjects aged 19 to 30, half of whom were cannabis users. For all subjects, they used ultrasound imaging to look at the heart and arteries.
They measured arterial stiffness and arterial function, or the ability of arteries to appropriately expand with greater blood flow. All three measures are indicators of cardiovascular function and potential disease risk.
Arterial stiffness was greater in cannabis users than in non-users. The team measured how fast a pressure wave travelled down the artery; stiffer arteries transmit a wave more quickly.
In cannabis users, cardiac function – inferred from how the heart moves as seen in echocardiographic images – was lower than in non-users.
Cheung said the team was surprised to see no difference in artery dilation in response to changing blood flow.
All three measures normally change in cigarette smokers, with stiffer arteries and lower vascular and heart function.
“We don’t yet know why in cannabis users there’s no difference in vascular function,” he said. Cheung said differences may reflect variations in how tobacco and cannabis are consumed, as well as amounts and frequency and the user’s age.
“We looked at young cannabis users. In the cigarette literature, heavy, long-term smokers show reduced vascular function but that’s not necessarily the case for younger smokers.”
The University of Guelph researchers plan further studies to learn about potential impacts of these changes and disease risk in people who use cannabis.
“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,” said Burr.
“It also paves the way to our next studies, aimed at understanding the direct effects of cannabis consumption, and how this may interact with common stressors of everyday life, like exercise.”
Cheung emphasised the fact that few studies have been done on the impacts of cannabis use on cardiovascular health. “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.”
Study details
Habitual cannabis use is associated with altered cardiac mechanics and arterial stiffness, but not endothelial function in young healthy smokers
Christian P Cheung, Alexandra M Coates, Philip J Millar and Jamie F Butt
Affiliation: University of Guelph in Ontario, Canada.
Published in the Journal of Applied Psychology on 11 March 2021.
Abstract
Cigarette smoking is among the most detrimental behaviours to cardiovascular health, resulting in arterial stiffening, endothelial dysfunction and structural/functional alterations to the myocardium.
Similar to cigarettes, cannabis is commonly smoked, and next to alcohol, is the most commonly used recreational substance in the world. Despite this, little is known about the long-term cardiovascular effects of smoking cannabis.
This study explored the associations of cardiovascular structure and function with cannabis use in ostensibly healthy young participants (n = 35). Using echocardiography, carotid-femoral pulse wave velocity (cfPWV), and brachial flow-mediated dilation (FMD), we performed a cross-sectional assessment of cardiovascular function in cannabis users (n= 18) and controls (n = 17).
There were no differences in cardiac morphology or traditional resting measures of systolic or diastolic function between cannabis users and controls (all P > 0.05), whereas cannabis users demonstrated reduced peak apical rotation compared with controls (cannabis users: 5.5 ± 3.8, controls: 9.6 ± 1.5; P = 0.02).
Cannabis users had higher cfPWV compared with controls (cannabis users: 5.8 ± 0.6 m/s, controls: 5.3 ± 0.7 m/s; P = 0.05), whereas FMD was similar between cannabis users and controls (cannabis users: 8.3 ± 3.3%, controls: 6.8 ± 3.6%; P = 0.7).
Young, healthy, and cannabis users demonstrate altered cardiac mechanics and greater aortic stiffness. Further studies should explore causal links between cannabis smoking and altered cardiovascular function.
New and noteworthy
Recreational cannabis is the most widely used substance in the world, other than alcohol. Yet, the effects of cannabis use on cardiovascular function and health are not well understood.
Our cross-sectional data demonstrate that young, ostensibly healthy cannabis users have greater arterial stiffness and altered cardiac mechanics compared to nonusers. These findings suggest that cannabis users may be at greater risk of the development of future cardiovascular disease.
SEE ALSO FROM THE MEDICALBRIEF ARCHIVES
Cannabis legalisation a ‘significant concern’ – American Heart Association
Drinking, smoking, drug use linked to premature heart disease in the young
Cannabis reduces blood pressure in older adults – Israeli research
We should not allow a cannabis free-for-all – Yale ethicist