Large Observational Study Finds No Correlation Between Marijuana Use and Increased Stroke Risk

A retrospective observational study published in Neurology Clinical Practice examined the connection between marijuana use and stroke risk. Some previous studies have found self-reported marijuana use increased stroke risk, whereas others have found no increased risk of stroke with marijuana use. 

This study relied on a review of all charts over a 3-year period. After researchers adjusted for other factors that affect stroke risk (age, high blood pressure, high cholesterol, sickle cell disease, obesity, diabetes, smoking, and heart conditions), there was no correlation between recent marijuana use verified with a urine drug screen and an increase or decrease risk of stroke. 

The study involved participants (n=9,350) age 18 years or more, who had been admitted to a hospital and screened with a urine test for drug use. A total of 1,643 participants (18%) tested positive for marijuana. Those who tested positive were more likely to be male, younger, and current marijuana users than those who tested negative. Those who tested positive for drugs other than marijuana were excluded from the study.Of those who tested positive, 130 of 1,643 participants (8%) had an ischemic stroke. Of those who tested negative, 1,207 of 7,707 people (16%) had an ischemic stroke. 

“Previous studies that investigated cannabis use and risk of stroke have had conflicting results, some showing a decreased risk and others showing a greatly increased risk,” said Carmela V. San Luis, MD, University of Mississippi, Jackson. “Our observational study looked specifically at recent cannabis use by reviewing drug testing data for people admitted to the hospital. While more research is needed with larger numbers of people, our study lends support to the studies showing that cannabis use does not increase the risk of stroke.”