Cannabis Users Had 48% Higher Risk of Cardiovascular Events in Large Meta-Analysis | Research

The takeaway

A meta-analysis of 17 studies involving nearly 1.9 million people found cannabis use was significantly associated with a 48% higher risk of composite adverse cardiovascular events, though individual associations with heart attack and stroke did not reach statistical significance.

Cardiologists, primary care physicians, cannabis users with cardiovascular risk factors, and public health officials.

What the researchers found

Ever use of cannabis was associated with a statistically significant 48% higher risk of any adverse cardiovascular event (RR: 1.48, 95% CI: 1.16-1.90, p=0.002). The association with myocardial infarction alone (RR: 1.25, 95% CI: 0.91-1.71) and stroke alone (RR: 1.38, 95% CI: 0.88-2.16) did not reach statistical significance.

Why it matters

Whether cannabis causes cardiovascular disease has been debated for years. This meta-analysis of nearly 1.9 million people provides the strongest pooled estimate to date, showing a significant association with composite cardiovascular events even if individual endpoints fall short of significance.

The numbers in context

17 studies, 1,902,481 individuals. Mean follow-up: 8.5 years. Any adverse CV event: RR 1.48 (95% CI: 1.16-1.90, p=0.002). MI: RR 1.25 (95% CI: 0.91-1.71, p=0.17). Stroke: RR 1.38 (95% CI: 0.88-2.16, p=0.16). Age range: 18-74 years.

How the study worked

Systematic review and meta-analysis of 17 observational studies (PubMed, Scopus, ScienceDirect, Cochrane) from inception to April 2024. Random effects models analyzed 1,902,481 individuals aged 18-74 with mean follow-up of 8.5 years. Registered with PROSPERO (CRD42024530366).

What this study cannot tell us

All included studies were observational, limiting causal inference. Cannabis exposure was typically 'ever use,' which does not capture dose, frequency, or potency. Confounders like tobacco co-use may not be fully controlled. Publication bias possible. Heterogeneity across study designs and populations.

How to read the evidence

Large pooled analysis with PROSPERO registration and appropriate methodology, but observational data with crude exposure measures and potential residual confounding.

When this study was published

Published 2025, searching literature through April 2024.

The bigger picture

The non-significant individual associations for heart attack and stroke combined with a significant composite endpoint suggest that cannabis may increase overall cardiovascular risk through multiple pathways rather than one dominant mechanism. This pattern is consistent with cannabis's known effects on blood pressure, heart rate, and vascular inflammation.

Questions still open

Whether dose-response relationships exist between cannabis frequency and cardiovascular risk
How much of the observed risk is attributable to smoked versus non-smoked cannabis

Common questions

Does cannabis cause heart attacks?

This meta-analysis found an association but cannot prove causation. The 25% higher heart attack risk for cannabis users was not statistically significant on its own. However, the significant 48% increase in overall cardiovascular events suggests cannabis may affect heart health through multiple mechanisms.

How does this compare to tobacco's cardiovascular risk?

Tobacco smoking roughly doubles cardiovascular risk. The 48% increase associated with cannabis is smaller but still clinically meaningful, especially since many cannabis users also smoke tobacco, potentially compounding the risk.

Read the original research

Cannabis use and atherosclerotic cardiovascular disease outcomes: A meta-analysis of multinational cohort data.

Disease-a-month : DM, 71(3), 101849

View on PubMed ↗Publisher’s paper ↗

Citation

Sebastian, Sneha Annie; Shah, Yash; Arsene, Camelia; Krishnamoorthy, Geetha. (2025). Cannabis use and atherosclerotic cardiovascular disease outcomes: A meta-analysis of multinational cohort data.. Disease-a-month : DM, 71(3), 101849. https://doi.org/10.1016/j.disamonth.2024.101849