Long-term cannabis use may not increase heart attack risk, new study finds—but many questions remain

Another noteworthy takeaway from this analysis was the fact that, among participants with a history of monthly cannabis use, individuals who had not used it recently faced “significantly greater odds” of experiencing a MI than more recent users. This was “somewhat unexpected,” Corroon et al. wrote, “given the known acute cardiovascular effects of cannabis use, other studies reporting associations with recent use and the shorter duration of exposure in this group.”

What did the authors make of this finding?

“It is conceivable that subjects with a history of monthly cannabis use may have ceased usage earlier owing to health-related concerns that may have otherwise contributed to an increased risk of CVD,” they wrote. “If this phenomenon exists, it may be comparable to the ‘smoker’s paradox’ evident in tobacco research, in which cigarette smokers may receive more intensive medical interventions at a younger age and consequently exhibit better outcomes than do current smokers or never smokers. This finding warrants further investigation.”

The authors concluded by calling for additional research on this topic, especially studies that can do a more exact job of quantifying cannabis use among test subjects, tracking the potency of any cannabis products being used, etc.

“Given the expanding access to cannabis products in the United States and around the world, more research, particularly longitudinal and experimental studies, is needed,” the group wrote.  

Another perspective on cannabis use and cardiovascular health

Kristie M. Harris, PhD, a health psychologist with Yale School of Medicine, wrote a separate commentary about these findings for the American Journal of Cardiology.[2]

“Investigation of the cardiovascular effects of cannabis use is of particular importance given the distribution of cannabinoid 1 receptors in the myocardium, aorta smooth muscle and vascular endothelium, and the well-documented effects of acute cannabis use on physiological processes associated with cardiovascular risk, including greater sympathetic nervous system activation, endothelial dysfunction and oxidative stress,” Harris explained. “How this translates into risk for major cardiovascular events, such as MI, remains unclear however, largely due to methodological limitations of currently available data.”

Harris noted that much more clinical research is needed that examines the potential long-term impact cannabis may have on a person’s health, especially as access to cannabis continues to increase throughout the United States. She also noted that tobacco use is an ongoing problem for research teams trying to examine this topic, creating challenges that the industry is still looking to solve.

“Our understanding of the cardiovascular effects of cannabis use is in its nascent stage, and more rigorous, prospective, longitudinal study is needed to understand the discrepancy between Corroon et al.’s findings and earlier mechanistic studies on acute cannabis effects and epidemiological studies of recent use and MI risk,” she wrote. “Such investigations should also more accurately reflect the current landscape of cannabis products which has evolved rapidly since the period of observation in Corroon et al.—with greater access and commercialization leading to expanded routes of administration and more potent formulations.”