Study Links Legal Cannabis to Higher Heart Hospitalization Rates in Western U.S.

Researchers analyzing 50,042,564 hospital discharge records from 2012 to 2018 found a statistical link between recreational marijuana legalization and increased cardiovascular hospitalizations in the western United States. The study, published in BMJ Open on October 22, compared regions that had legalized recreational sales against areas that had not during the study period.

For every additional year of legal recreational cannabis sales, the data showed a 3.7% relative increase in heart failure hospitalizations. Heart attack admissions rose by 3.1% per year of legalization. Hospitalizations for atrial fibrillation and atrial flutter, conditions involving abnormal heart rhythms, increased by 2.3% annually in these regions compared to the comparison group.

The researchers did not track individual patient histories to confirm marijuana use. They also did not determine the specific products consumed, the frequency of use, or the exact levels of tetrahydrocannabinol, or THC, exposure. Because the study was observational, the authors stated that the findings do not establish a direct cause and effect relationship.

Centers for Disease Control and Prevention data indicates that cannabis use can temporarily raise heart rate and blood pressure immediately after consumption. THC may also stimulate the nervous system and increase the heart's demand for oxygen. For individuals with preexisting cardiovascular conditions, such as high blood pressure, coronary artery disease, or a history of heart attack, these temporary changes can create additional physiological stress.

A separate 2024 study in the Journal of the American Heart Association examined survey responses from 434,104 American adults. That research found that people who reported daily cannabis use had 25% higher odds of reporting a heart attack and 42% higher odds of reporting a stroke. These associations persisted after researchers accounted for cardiovascular risk factors, including tobacco use.

The American Heart Association has warned that cannabis may interact with certain medications, including blood thinners and drugs used to manage cardiovascular conditions. Medical professionals advise patients to disclose all forms of cannabis use, including edibles and vaping products, to their doctors to evaluate potential risks and medication interactions.

The new study did not compare different consumption methods. It therefore could not determine whether smoking, vaping, or eating edibles contributed more significantly to the observed hospitalization trends. Researchers noted that future investigations must examine specific THC concentrations and consumption methods to clarify the relationship between legal access and cardiovascular health outcomes.