Portland’s favorite greenery might be helping you relax a bit too much—especially your heart. Two new studies tie marijuana use to increased risk of heart failure and heart attack. 

Portland, it goes without saying, is big on weed, with one of the nation’s highest concentrations of cannabis dispensaries (13.7 per 100,000 residents) and 240 OLCC-registered pot shops in Multnomah county alone. As the drug settles into American culture—38 states have legalized medical cannabis—researchers are able to study its long-term effects at a large scale. 

The first study followed 156,999 participants in the National Institutes of Health–sponsored All of Us Research Program. It found a 34 percent increased risk of developing heart failure in marijuana users compared to those who reported never using marijuana. Starting in 2016, the study followed people for an average of four years, adjusting for factors like socioeconomic status, as well as alcohol intake and drug use. They focussed on nonmedical marijuana users, or those that use the drug in quantities beyond a medical prescription, and did not differentiate between how participants ingested it (the study acknowledges that whether cannabis is eaten or smoked may shift its health effects). 

“Our results should encourage more researchers to study the use of marijuana to better understand its health implications, especially on cardiovascular risk,” the study’s lead author Yakubu Bene-Alhasan, a resident physician at Medstar Health in Baltimore, said in a press release.

Another study looked at the effect cannabis use has on elderly hospital patients with pre-existing heart conditions. Their data comes from the 2019 National Inpatient Sample, the largest nationwide database of hospitalization records, with over 10.5 million patient records (the study acknowledges that this large dataset, and the variables in collection, may affect its accuracy). Specifically, researchers were interested in patients 65 and over that didn’t use tobacco. They found marijuana users 20 percent more likely to have major heart or brain events while hospitalized. 

Both studies will be presented next week at the American Heart Association’s Scientific Sessions 2023 and add to an ongoing body of research. “Marijuana use isn’t without its health concerns,” Bene-Alhasan said, “and our study provides more data linking its use to cardiovascular conditions.”