Young Adults Who Use Cannabis Have Worse Outcomes After Heart Attacks | Research

The takeaway

Among patients under 45 hospitalized for heart attacks, cannabis users (41% of the cohort) had significantly higher rates of major cardiovascular events over a median 3-year follow-up.

Young adults who smoke both tobacco and cannabis, cardiologists treating young heart attack patients, and researchers studying cannabis cardiovascular effects.

What the researchers found

This French study followed 188 patients under age 45 who were hospitalized for acute coronary syndrome (heart attacks and unstable angina)—all of whom were tobacco smokers. At admission, 41% tested positive for cannabis via urine testing.

Over a median follow-up of nearly 3 years, cannabis users had significantly higher rates of major adverse cardiovascular events (MACE)—a composite of death, stroke, recurrent heart attack, arrhythmia, and heart failure events. The weighted survival curves diverged significantly (p = 0.002).

The propensity-weighted analysis is important: the researchers used statistical techniques to adjust for socioeconomic and cardiovascular risk factors, trying to isolate the cannabis effect from other differences between the groups. Even after this adjustment, the association persisted.

That all participants were tobacco smokers strengthens the finding in one respect—it removes tobacco as a confounder—but also means the study is examining cannabis's cardiovascular impact on top of an already high-risk behavior. Whether cannabis would show the same association in non-smokers is unknown.

The 41% cannabis use rate among young heart attack patients is itself striking, suggesting cannabis use is very common in this population.

Why it matters

Heart attacks in young adults are uncommon but devastating, and understanding modifiable risk factors is critical for prevention. The 41% cannabis use rate in this population raises the question of whether cannabis contributes to both the initial event and the worse outcomes afterward. Combined with RTHC-00167's findings in older veterans with heart disease, the cardiovascular signal from cannabis is emerging across age groups.

The numbers in context

N = 188, all under 45, all tobacco smokers. 77 (41%) tested positive for cannabis. Median follow-up: 2.93 years. Propensity-weighted survival curves: p = 0.002 for MACE difference.

How the study worked

Retrospective single-center cohort study. 188 patients under 45 admitted for acute coronary syndrome between January 2010 and March 2025, all current tobacco smokers. Cannabis use determined by urinary testing at admission. Propensity-weighted analysis adjusted for socioeconomic and cardiovascular risk factors. Primary endpoint: MACE (death, stroke, MI, arrhythmia, heart failure). Cox model truncated at 6 years.

Who was studied

N=188 patients under 45 years, all current tobacco users, admitted for acute coronary syndrome in a single center.

What this study cannot tell us

Single-center French study with a relatively small sample. Retrospective design. All participants smoked tobacco, so results can't be generalized to non-smokers. Urinary cannabis testing at admission captures recent use but not frequency, dose, or chronicity. Residual confounding is possible despite propensity weighting. No data on cannabis route of administration or product type.

How to read the evidence

Retrospective cohort with propensity-weighted analysis—stronger than simple observational data but weaker than a prospective design. Published in Heart (British Cardiac Society).

When this study was published

Published in 2025 with 15 years of data (2010–2025), providing long-term follow-up in a young population.

The bigger picture

This is the younger counterpart to RTHC-00167's study of 4,285 veterans (average age 67) with coronary artery disease. Together, they suggest cannabis may affect cardiovascular outcomes across the age spectrum—in young adults who are just developing heart disease and in older adults who already have it. The fact that both smoking-specific and any-use analyses showed associations suggests the cardiovascular risk may extend beyond combustion byproducts.

Replication

Not stated in abstract.

Funding

Not reported in abstract.

Conflicts of interest

Not reported in abstract.

Questions still open

Would cannabis-only users (no tobacco) show the same cardiovascular risk? Is the mechanism related to acute THC effects on heart rate and blood pressure, chronic vascular inflammation, or both? Should young heart attack patients be screened for cannabis use and counseled about cardiovascular risks?

Read the original research

Cannabis use among young adults with acute coronary syndrome: impact on initial presentation and long-term prognosis.

Heart (British Cardiac Society)

Heart is a reputable journal published by the British Cardiac Society, focusing on cardiovascular research.

View on PubMed ↗Publisher’s paper ↗

Citation

Martin, Nicolas; Beyls, Christophe; Zeitouni, Michel; Bohbot, Yohann; Stracchi, Valentin; Sroutta-Paillusseau, Sofiane; Jarry, Geneviève; Bodeau, Sandra; Noé, Fabio; Hudelo, Julien; Fournier, Alexandre; Malaquin, Dorothée; Gabrion, Paul; Landemaine, Thomas; Vernier, Agathe; Kubala, Maciej; Leborgne, Laurent; Hermida, Alexis. (2025). Cannabis use among young adults with acute coronary syndrome: impact on initial presentation and long-term prognosis.. Heart (British Cardiac Society). https://doi.org/10.1136/heartjnl-2025-326777