Study Finds No Association Between Cannabis Use And Risk Of Stroke

Researchers who analyzed the medical records of hospital patients found no association between recent cannabis use and stroke risk, according to a recent study. A report on the research, “Association Between Recent Cannabinoid Use and Acute Ischemic Stroke,” was published earlier this month in the peer-reviewed journal Neurology: Clinical Practice.

To conduct the research, a team of investigators working with the University of Mississippi’s Department of Neurology reviewed medical records to determine if those testing positive for recent cannabis use when admitted to the hospital were more likely to experience an ischemic stroke. An ischemic stroke is a stroke caused by a blockage of a blood vessel, such as a blood clot.

Noting that prior research on the potential association between cannabis use and stroke risk has been inconsistent, neurologist and study lead author Carmela V. San Luis said that her team had discovered no link between the two.

“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,” San Luis said in a press release. “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.”

Research Details

The research included 9,350 people 18 and older who had been given a urine screening for drugs upon being admitted to a hospital. Those who tested positive for more than one drug were excluded from the study. A total of 1,643 patients, or 18%, tested positive for cannabis use. Those who tested positive for cannabis were more likely to be male, younger, and current smokers than those who tested negative.

Of those who tested positive for cannabis, 130, or 8%, had an ischemic stroke. Of the 7,707 who tested negative, 1,207 or 16%, had an ischemic stroke. However, when adjustments were made for other factors that are associated with an increased risk of stroke including age, high blood pressure, high cholesterol, sickle cell disease, obesity, diabetes, smoking, and heart conditions, the researchers found neither an increased or decreased risk of ischemic stroke.

Because the study was observational, the results do not prove that cannabis use does not increase the risk of stroke, only that researchers found no association. The team also noted some limitations of the study, including a lack of information on the patients’ prior history with cannabis and the amount used before hospitalization. Other limitations include an inability to adjust for some factors such as a lack of physical activity and body mass index. More research is still needed, according to the investigators.

“Our research adds to the list of studies with conflicting results, so it is important to continue to investigate stroke risk and cannabis use,” said San Luis. “Future studies are now needed in larger groups of people that not only include data from drug screenings but also dosing amounts as well as a person’s history of cannabis use.”