Does Smoking Cannabis Increase Heart Attack and Stroke Risk in Older Veterans? | Research

The takeaway

In 4,285 veterans with coronary artery disease (average age 67), smoking cannabis was associated with higher rates of cardiovascular events—but the findings require careful interpretation given confounders.

Older adults with heart disease who use cannabis, cardiologists managing patients who use cannabis, and researchers studying cardiovascular risks of cannabis.

What the researchers found

This is one of the largest and most rigorous studies to examine whether cannabis smoking affects cardiovascular outcomes in people who already have heart disease. The THC Cohort (Heart and Cannabis) followed 4,285 veterans with coronary artery disease, all born between 1950 and 1952, from their initial interview through follow-up.

Participants were classified by their self-reported cannabis smoking status in the past 30 days. The primary outcome was a composite of fatal and nonfatal stroke, fatal and nonfatal heart attack, and cardiovascular death.

The study found an association between cannabis smoking and higher rates of these cardiovascular events. In a separate analysis, any form of cannabis use (smoking, vaping, or edibles) versus nonuse was also examined.

Several features make this study notable. The population is highly relevant—older adults with existing heart disease who are increasingly using cannabis as it becomes legal. The VA dataset provided comprehensive clinical data from both interviews and medical records (VA and Medicare). And the birth cohort design (all participants born 1950–1952) controls for generational differences in cannabis exposure and attitudes.

However, the observational design means the association could be confounded by differences between cannabis users and non-users that weren't fully captured—lifestyle factors, other substance use, or unmeasured health behaviors.

Why it matters

The intersection of aging, heart disease, and cannabis use is becoming a critical clinical question as baby boomers—the generation most likely to have used cannabis historically—age into the highest-risk period for cardiovascular disease. This study provides the first large-scale data on that intersection, though it can't definitively answer whether cannabis causes cardiovascular events or merely correlates with other risk factors.

The numbers in context

N = 4,285. Mean age 67.5 years. 2% female. All had coronary artery disease. Recruited 2018–2020. Primary outcome: composite of stroke, MI, and cardiovascular death.

How the study worked

Prospective observational cohort study. 4,285 veterans (mean age 67.5, 2% female) with coronary artery disease, born 1950–1952, recruited April 2018 to March 2020. Cannabis smoking status classified by self-report in the past 30 days. Separate analysis for any cannabis use (smoking, vaping, edibles). Primary outcome: composite of fatal/nonfatal stroke, fatal/nonfatal MI, and cardiovascular death. Data from telephone interviews, VA records, and Medicare claims.

Who was studied

N=4,285 veterans aged 66-68, 2% female, with coronary artery disease in the US.

What this study cannot tell us

Observational design—cannot prove causation. Overwhelmingly male (98%) veteran population limits generalizability. Self-reported cannabis use may underestimate true prevalence. Confounders like tobacco smoking, alcohol use, and medication adherence could drive the association. The 30-day use window is a crude measure that doesn't capture dose, frequency, or potency.

How to read the evidence

Large prospective cohort with a focused high-risk population and comprehensive data sources, but observational design limits causal inference.

When this study was published

Published in 2025 in Circulation (a top cardiovascular journal) with data from 2018–2020.

The bigger picture

This adds to the cardiovascular-cannabis evidence base alongside studies examining younger and healthier populations. The fact that the study focused on people with existing heart disease is important—most prior cardiovascular-cannabis studies involved general populations where baseline cardiovascular risk is low. For this high-risk group, even small increases in cardiovascular risk from cannabis could translate to meaningful clinical consequences. The route-of-administration analysis (smoking vs. any use) also matters, since smoking involves combustion byproducts that are independently harmful to blood vessels.

Replication

Not stated in abstract.

Funding

Not reported in abstract.

Conflicts of interest

Not reported in abstract.

Questions still open

Is the cardiovascular risk from cannabis specific to smoking (combustion) or present with all routes of administration? Would edibles or tinctures carry less cardiovascular risk in this population? Should cardiologists screen for cannabis use in patients with coronary artery disease?

Read the original research

Association of Smoking Cannabis With Cardiovascular Events Among Veterans With Coronary Artery Disease.

Circulation, 152(6), 352-365

Circulation is a well-respected journal focusing on cardiovascular medicine.

View on PubMed ↗Publisher’s paper ↗

Citation

Keyhani, Salomeh; Cohen, Beth E; Vali, Marzieh; Hoggatt, Katherine J; Bravata, Dawn M; Austin, Peter C; Lum, Emily; Hasin, Deborah; Grunfeld, Carl; Shlipak, Michael G. (2025). Association of Smoking Cannabis With Cardiovascular Events Among Veterans With Coronary Artery Disease.. Circulation, 152(6), 352-365. https://doi.org/10.1161/CIRCULATIONAHA.124.073193