Smoking cannabis may not impact heart health of older CAD patients
Smoking cannabis does not significantly increase the risk of experiencing an adverse cardiovascular event in older patients with coronary artery disease (CAD), according to new findings published in Circulation.[1]
“Smoking cannabis causes a five-fold increase in the blood carboxyhemoglobin level and a three-fold increase in the quantity of tar inhaled compared with tobacco smoke,” wrote first author Salomeh Keyhani, MD, MPH, a professor of medicine with the University of California, San Francisco, and colleagues. “Cannabis smoke in rat models has a more prolonged impact on endothelial dysfunction than tobacco smoke, although studies in healthy young adults are mixed. Therefore, like tobacco smoke, cannabis smoke may precipitate atherosclerosis, coronary disease and cardiovascular events. Despite these experimental studies demonstrating that cannabinoids have potential cardiovascular health effects and the predominance of smoking as the most common form of cannabis use, very few longitudinal studies have examined the association of cannabis use and cardiovascular events.”
Keyhani et al. tracked data from more than 4,000 U.S. veterans with a mean age of 67.5 years old. Just 2% of patients were women. While 1,015 patients reported smoking cannabis in the past 30 days, 510 of those individuals said they smoked it daily. The mean follow-up period was 3.3 years, and 563 patients experienced the study’s primary outcome—a composite of fatal and nonfatal stroke, fatal and nonfatal acute myocardial infarction and cardiovascular death—during that time.
Overall, the group found that there were “no statistically significant associations” between smoking cannabis and adverse cardiovascular events. In addition, patients who said they smoked daily did not face any additional risks when it came to adverse cardiovascular events.
The authors also found that study participants who consumed cannabis in any way—smoking it, vaping it or eating it as part of an edible—did not increase their risk of an adverse cardiovascular event.
“To our knowledge, this is the first well-powered study to evaluate associations of self-reported cannabis use and longitudinal cardiovascular disease risk,” the authors wrote. “We hypothesized that cannabis use would be associated with greater risk of recurrent cardiovascular events. This hypothesis was mainly informed by cross-sectional studies, which had found cannabis use to be associated with increased cardiovascular risks.”
Keyhani and colleagues emphasized that these patients already presented with multiple risk factors. In addition to presenting with established CAD, many of them were also physically inactive or had a history of diabetes, heart failure or chronic kidney disease.
“Cannabis use may be a less important factor in the setting of prevalent disease and numerous competing risk factors,” the group wrote.
Another key takeaway from this study was the fact that either 90% of study participants were either current or former tobacco users.
“Although our intention was to recruit high-risk participants to maximize the event rate during a short follow-up period, we might have selected a population among whom it was too challenging to detect an association of smoking cannabis with cardiovascular events,” the authors wrote. “Prospective studies with thorough exposure assessment in the general population and among lifetime tobacco abstainers may be needed to examine the association of cannabis use with the incidence of cardiovascular events. However, our study and other studies also suggest that developing such a cohort may be challenging given the high prevalence of tobacco use among those who smoke cannabis.”
Click here to read the full analysis.
In addition, read about recent studies highlighting the potential harms of cannabis use here and here.
Michael has more than 19 years of experience as a professional writer and editor. He has written at length about cardiology, radiology, artificial intelligence and other key healthcare topics.