Young adult pot smokers who've suffered a stroke are more likely to have another stroke if they keep toking, a new study finds.
Research has already linked heavy cannabis use with an increased risk of stroke, but this new study showed that risk remains high even after a first stroke, with pot users nearly 50% more likely to have a second stroke than non-users.
"It is essential to increase awareness among younger adults of the adverse impact of chronic, habitual use of marijuana, especially if they have established cardiovascular disease risk factors or previous stroke episodes," said lead researcher Dr. Akhil Jain, a resident physician at Mercy Fitzgerald Hospital in Darby, Pa.
Stroke rates are increasing among adults aged 18 to 45, according to the American Heart Association, with young adults accounting for up to 15% of strokes in the United States. This study shows pot use might be one reason why more strokes are happening in younger people.
"These data really do show us a red flag," said Robert Page, a professor of clinical pharmacy with the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences in Aurora, Colo.
"The fact of the matter is a lot people say cannabis is natural. No. It's like any other psychotropic medication. It has side effects, and sometimes those side effects are neurologic and cardiovascular in nature," Page added.
For the study, researchers analyzed data from the National Inpatient Sample, a database that compiles information on 7 million hospital stays every year, Jain said.
The researchers reviewed the cases of more than 161,000 people aged 18 to 44 who were hospitalized for either a stroke or a transient ischemic attack (TIA) -- a temporary blockage of blood flow to the brain that some refer to as a "mini-stroke" -- between 2015 and 2017.
Out of those patients, nearly 4,700 also had been diagnosed with cannabis use disorder, the researchers said.
Nearly 7% of people with cannabis use disorder wound up hospitalized for a second stroke, compared with just over 5% of those who didn't habitually smoke pot, the findings showed.
"Patients with cannabis use disorder were 48% more likely to have been hospitalized for recurrent stroke than those without it," Jain said.
The chemical components of marijuana are one suspected culprit for this increased stroke risk, Page said -- particularly THC, the compound that causes intoxication.
THC can cause the blood vessels in the brain to constrict and tighten, which increases the possibility of a stroke, Page said.
"We believe that occurs in a concentration-dependent manner," Page said. "The more that you use, the increased possibility for an acute stroke."
It's hard to say whether pot smoking is worse for you than cigarette smoking at this point, Page added. More study is needed to compare the effects of nicotine and other tobacco compounds with those of the chemicals found in pot.
However, it's likely that heavy pot smokers are compounding their risk by also smoking tobacco, Jain said.
"We did not directly compare re-strokes in [tobacco] smokers with cannabis users, but we did find in our analysis that patients with cannabis use disorder had a higher associated prevalence of tobacco smoking (73.9%) than patients without cannabis use disorder (39.6%)," Jain said.
"For our final report, we took into account this factor of overlapping use of smoking and cannabis, and still found higher chances of re-stroke in patients with cannabis use disorder," Jain continued.
Jain will present the findings at the upcoming annual meeting of the American Stroke Association, which will take place in New Orleans from Feb. 8 to 11. Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.
The U.S. Centers for Disease Control and Prevention has more on the health effects of marijuana.
SOURCES: Akhil Jain, MD, resident physician, Mercy Fitzgerald Hospital, Darby, Pa.; Robert Page, PharmD, MSPH, professor, clinical pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, Colo.; American Stroke Association, annual meeting, Feb. 8 to 11, 2022