Cannabis Use and Heart Attack Risk: 2025 Research Findings

Cannabis Use Linked to Increased Heart Attack Risk

Recent research presented at the American College of Cardiology's Annual Scientific Session (ACC.25) and published in JACC Advances indicates that cannabis users have a substantially higher risk of suffering a heart attack compared to non-users. This risk persists even among younger adults who are otherwise healthy and free of significant cardiovascular comorbidities.

Two primary studies provide the basis for these findings:

1. Retrospective Study: Analyzing data from over 4.6 million people via the TriNetX global health research network, researchers found that cannabis users under age 50 were over six times as likely to suffer a heart attack. This cohort also showed a fourfold increased risk of ischemic stroke, a twofold increased risk of heart failure, and a threefold increased risk of combined cardiovascular death, heart attack, or stroke.
2. Meta-Analysis: A pooled analysis of 12 studies involving over 75 million people showed that active cannabis users are 1.5 times (a 50% increase) more likely to suffer a heart attack than non-users.

Proposed Biological Mechanisms

While the exact mechanisms are not fully understood, researchers hypothesize that cannabis impacts the cardiovascular system through several pathways:

• Heart Rhythm Regulation: Cannabis may interfere with the heart's electrical signaling and rhythm.
• Oxygen Demand: Use may heighten the heart muscle's demand for oxygen.
• Endothelial Dysfunction: Cannabis may contribute to the inability of blood vessels to relax and expand, which interrupts blood flow.
• Acute Risk: One study within the meta-analysis noted that the risk of heart attack peaks approximately one hour after consumption.

Study Limitations and Confounding Factors

Researchers and medical professionals have cautioned that these findings should be interpreted with care due to thet retrospective nature of the data and the lack of control for several critical variables.

Unaccounted Variables

Lead author Ibrahim Kamel, MD, noted that cannabis consumption is often associated with other substances that were not accounted for in the studies, including:

• Tobacco and Nicotine: The act of smoking cannabis often involves inhaling burnt particulates or mixing cannabis with tobacco, both of which are known cardiovascular risks.
• Other Illicit Drugs: Use of substances such as cocaine may correlate with cannabis use and contribute to the heart attack risk.
• Dosage and Method: The studies did not account for the duration of use, the amount of cannabis consumed, or whether the drug was ingested (edibles) versus smoked.

Data Source Limitations

Because the data was derived from electronic medical records (EMR), the findings rely on patients being honest with their physicians about their cannabis use. This introduces potential reporting bias and limits the ability to draw a definitive causal link.

Community Perspectives and Clinical Implications

Technical and medical discussions surrounding these findings highlight several key counterpoints and observations:

• The "Smoking" Variable: Many observers argue that the risk may be attributed to the inhalation of combustion products rather than the THC/CBD components themselves. There is a noted lack of data specifically comparing edible users to smokers.
• Heart Rate Elevation: Some users and researchers point to the well-documented effect of THC increasing heart rate (tachycardia), which may contribute to acute cardiovascular stress.
• Socioeconomic Correlations: Some analysts suggest that cannabis use may correlate with other heart-health variables, such as income level or stress, which could inflate the reported odds ratios.

Clinicians are encouraged to include cannabis use in their standard cardiovascular risk workups, treating it with similar importance to screening for cigarette smoking to better understand a patient's overall heart health.