Cannabis Linked to Increased Risk of Cardiovascular Disease

Cannabis use has been on a steady rise in recent years, with medical or recreational cannabis sales now legal in more than half of U.S. states. But according to two new preliminary studies, regular cannabis use may raise the risk for heart failure, stroke or heart attack. And that's even after accounting for cardiovascular risk factors including Type 2 diabetes, high blood pressure, and obesity, 

The studies, which were conducted by separate research groups, will be presented at the American Heart Association’s Scientific Sessions 2023 later this month. In the first, researchers found that daily cannabis use raised the risk of developing heart failure by about one-third compared to those who reported never using cannabis.

The study followed 156,999 participants who were free from heart failure when they enrolled in the research program, and found over a four-year period that 2,958, or around 2 percent, developed heart failure. Those who reported daily cannabis use in an initial survey had a 34 percent increased risk of developing heart failure, compared to those who said they had never used cannabis. 

"Prior research shows links between marijuana use and cardiovascular disease like coronary artery disease, heart failure and atrial fibrillation, which is known to cause heart failure," said Dr. Yakubu Bene-Alhasan, lead author of the study and a resident physician at Medstar Health in Baltimore. "Marijuana use isn’t without its health concerns, and our study provides more data linking its use to cardiovascular conditions."

However, the study was limited in that the data that did not specify how participants consumed cannabis, and whether was inhaled or eaten. 

In the second study, researchers examined data from the 2019 National Inpatient Sample, the largest nationwide database of hospitalizations, to see whether hospital stays in patients who used cannabis were complicated by a cardiovascular event, such as heart attack, stroke, cardiac arrest, or arrhythmia.

Of 28,535 cannabis users who had existing cardiovascular risk factors such as high blood pressure, Type 2 diabetes, or high cholesterol; 20 percent had an increased chance of having a major heart or brain event while hospitalized compared to the group of 10,680,000 adults with the same risk factors who did not use cannabis. Likewise, nearly 14 percent of cannabis users with cardiovascular risk factors had a major adverse heart and brain event while hospitalized.

Patients who used cannabis also had a 7.6 percent rate of heart attacks compared to 6 percent of non-users, and were more likely to be transferred to other facilities.

"Since 2015, cannabis use in the U.S. has almost doubled, and it is increasing in older adults, therefore, understanding the potential increased cardiovascular risk from cannabis use is important," said Dr. Avilash Mondal, lead study author and a resident physician at Nazareth Hospital in Philadelphia. "What is unique about our study is that patients who were using tobacco were excluded because cannabis and tobacco are sometimes used together, therefore, we were able to specifically examine cannabis use and cardiovascular outcomes."

Interestingly enough, the finding come just months after the U.S. Department of Health and Human Services made the landmark recommendation to move cannabis from a Schedule I to a Schedule III controlled substance. But given that alcohol and tobacco are still legal when those substances cause increased risks of cardiovascular disease, it seems unlikely that the research will have an impact on the legality issues going forward.