Legalizing recreational cannabis in the United States was associated with a faster rise in hospital admissions for cardiovascular disease, according to an analysis of more than 50 million patient discharge records published in the open access journal BMJ Open. Admissions for atrial fibrillation, heart failure, and heart attack all climbed more quickly after the law took effect in the Western region of the country than in states without such legislation.

The researchers drew on the National Inpatient Sample, a database of hospital discharge diagnoses and patient demographics whose participating states cover roughly 97% of the US population, covering the years 2012 through 2018. They focused on the Western region—Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming—because it began legalizing recreational cannabis in January 2014, nearly five years before other regions. By 2018, over 98% of people in the Western region lived in, or bordered, a state with legal cannabis sales.

The team examined hospital admission rates for six cardiovascular conditions: acute heart failure, heart attack, atrial fibrillation or flutter, ischaemic stroke, venous thromboembolism, and ventricular tachycardia. For each diagnosis, they estimated baseline regional admission rates per 100,000 people using weighted data from the two years before the first legal sale of recreational cannabis, then compared trends before and after legalization in the Western region with regions that had not enacted such laws. In total, the analysis covered 50,042,564 hospital discharge records between 2012 and 2018.

Before the legislation, in 2012 and 2013, hospital discharge rates for the included diagnoses were actually lower in the Western region than in regions without the legislation. But after legalization, those rates rose faster in the West. The estimated change in admission rates for each year of legal cannabis sales was statistically significant for atrial fibrillation, at just over 2% higher; heart failure, at nearly 4% higher; and heart attack, at just over 3% higher, after adjusting for potentially influential factors. Rates for the other studied outcomes were also higher, but those increases did not reach statistical significance.

People admitted to hospital in the Western region during the study period were, overall, younger—average age 51 versus 55 elsewhere—lived in higher-income ZIP codes (26% versus 19%), and less often identified as White.

Cannabis use has the potential to affect cardiovascular health through various physiological mechanisms, the researchers explain. Legalization policies have also been associated with more widespread use of cannabis products, particularly among older people who are already at heightened risk of cardiovascular problems.

The study is observational, meaning it cannot establish cause and effect, and the researchers acknowledge several limitations. They were unable to separate out individual states or examine the method of cannabis use, such as whether products were smoked. Nor could they account for trends in illegal use. Even so, the authors note that while several studies have examined the association of recreational cannabis legalization with psychiatric conditions, substance use, emergency visits, and traffic accidents, theirs is the first to examine the association with cardiovascular hospitalizations.

“While an observational study cannot prove causality, our findings point to potential adverse effects of recreation legalisation on population health,” the researchers write. They add that, globally, the findings support a cautious approach to legalization laws accompanied by data collection on cardiovascular outcomes. The article, titled “Cannabis legalisation and cardiovascular hospitalisations in the United States: nationwide difference-in-differences analysis, 2012–2018,” was published on 22 October 2026 in BMJ Open, with the DOI 10.1136/bmjopen-2025-111050. The authors reported no relevant conflicts of interest; two authors’ time was supported by NIH training grants.

Subject of Research: The association between recreational cannabis legalization and cardiovascular hospital admissions in the United States

Article Title: US cannabis legalization linked to rise in cardiovascular hospital admissions

Article References: US cannabis legalization linked to rise in cardiovascular hospital admissions. Original publication (Bibliographic details unavailable.)

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Keywords: cannabis legalization, cardiovascular disease, hospital admissions, atrial fibrillation, heart failure, heart attack, BMJ Open, observational study, National Inpatient Sample, public health, United States, difference-in-differences