Marijuana legalization linked to more heart hospitalizations

Researchers analyzed more than 50 million hospital discharge records from 2012 to 2018 to examine the impact of recreational cannabis legalization on cardiovascular health. The study focused on the Western United States, where states began legal sales in 2014, and compared admission trends to other U.S. regions that had not yet legalized cannabis. The analysis used a difference‑in‑differences approach to estimate how hospitalization rates changed after legalization.

Key findings on heart admissions

Hospital admission rates for heart failure rose nearly 4% faster per year after legalization. Rates for heart attacks increased just over 3% and atrial fibrillation just over 2%. Stroke, deep‑vein clots and tachycardia also showed higher rates, but the increases were not statistically significant. Before legalization, the Western region had lower baseline rates than the rest of the country, but the post‑legalization trend reversed that pattern.

Because the study is observational, it cannot prove that cannabis caused the rise in admissions. The authors note several limitations, including the inability to distinguish individual state effects, the lack of data on how cannabis was used, and trends in illicit use that could confound the results. They argue that the findings suggest potential adverse effects of recreational legalization on population health and call for a cautious approach as well as continued data collection.

The study, published in the open‑access journal BMJ Open, is the first to link cannabis legalization with cardiovascular hospitalizations in the United States. It adds to a growing body of evidence that recreational cannabis use may carry risks for heart‑related conditions, especially in older adults who are already at higher risk. Further research is needed to clarify the mechanisms and causal relationships.