BMJ Open Analysis of 50 Million Records Ties Recreational Cannabis Laws to Faster Cardiovascular Admissions

Researchers compared discharge rates for six cardiovascular diagnoses across 50,042,564 records before and after January 2014 legalization in the West, using difference-in-differences adjusted for age, income, and demographics. Baseline rates were lower in the West, yet post-legalization slopes steepened significantly for atrial fibrillation, heart failure, and infarction while remaining non-significant for stroke, VTE, and ventricular tachycardia. The design cannot isolate individual states or route of administration and leaves concurrent trends in illicit use unmeasured.

Cannabis exerts acute hemodynamic effects via CB1-mediated tachycardia and endothelial dysfunction; older users, now the fastest-growing consumer group in legal markets, carry higher baseline cardiovascular risk. Earlier observational cohorts in NEJM and Circulation have reported similar signals for arrhythmia and infarction, yet lacked policy-level controls. The current findings align with those patterns but add a population-level before-after contrast that prior single-state reports missed.

Next steps require linkage of state sales data to individual-level records and prospective cohorts tracking THC potency and frequency. Without these, residual confounding by rising opioid or alcohol co-use cannot be excluded. Regulators should monitor age-stratified admission trends in newly legal states over the coming 24 months.