Introduction: Cannabis Use and Cardiovascular Health
In a study from the University of California, San Francisco, researchers found no evidence that cannabis use was associated with a higher risk of atrial fibrillation (AFib), a common type of irregular heartbeat. This observational study, published in the journal Heart Rhythm, adds to research on the relationship between cannabis use and cardiovascular health.
Study Details: Examining Cannabis and AFib Risk
The study used data from 150,554 UK Biobank participants with a mean age of 63, including people who had never used cannabis, occasional users (fewer than 100 times) and frequent users (more than 100 times). Over a mean follow-up of about six years, researchers identified new AFib diagnoses from medical records and, after adjusting for factors such as age, alcohol, smoking and existing heart conditions, found no statistically significant difference in AFib risk between cannabis users and people who had never used cannabis.
Key Findings: Challenging Previous Assumptions
Unlike most earlier studies, which were cross-sectional and often relied on diagnostic codes to identify cannabis users, this research followed recreational cannabis users over time. The researchers concluded that there was no evidence that cannabis use was associated with a higher risk of AFib, for either occasional or frequent users. They noted that they could not assess how cannabis was used or how much was used.
Broader Implications: Cannabis Use and Cardiovascular Events
AFib is known for increasing the risk of stroke and other adverse cardiovascular events. This study adds to research on cannabis and the heart, but finding no association with AFib in one cohort does not show that cannabis use is free of cardiovascular risk. A separate cross-sectional study of US adults found no association between current cannabis use and traditional risk factors for atherosclerosis (hardening of the arteries) or estimated long-term cardiovascular risk, although it did not measure heart attacks or strokes directly.
Understanding the Full Spectrum of Cannabis and Heart Health
While this study focuses on AFib, it is part of a larger conversation about cannabis and heart health. A 2023 meta-analysis of 20 observational studies found that cannabis use was not significantly associated with heart attacks, strokes or adverse cardiovascular events overall, but its authors advised caution because the studies differed considerably. However, problematic cannabis use may still pose cardiovascular risks: a study in the journal Addiction found that adults in Alberta, Canada, with cannabis use disorder had about a 60% higher risk of adverse cardiovascular events than matched adults without the disorder.
The University of California study is a useful contribution to our understanding of cannabis and cardiovascular health. It found no evidence that cannabis use was associated with a higher risk of atrial fibrillation in this cohort, but as an observational study it cannot rule out risk or show cause and effect, and it could not assess the method or amount of use. It supports more nuanced discussions about cannabis use and health. Read more in our article on cannabis use in the US and Canada.
