SOURCES: Richard Libman, M.D., vice chair, neurology, Long Island Jewish Medical Center, New Hyde Park, N.Y.; Journal of the American College of Cardiology, news release, Oct. 26, 2015
MONDAY, Oct. 26, 2015 (HealthDay News) -- Young adults who use marijuana are more likely to suffer strokes caused by narrowing of the arteries in the skull than those who don't use the drug, a new study finds.
Prior research has identified a link between marijuana use and stroke, but this study is the first to examine differences in stroke between marijuana users and non-users. The findings may help efforts to pinpoint what causes strokes in marijuana users, the researchers said.
A team led by Dr. Valerie Wolff, at the University Hospital of Strasbourg in France, examined 334 patients younger than 45 who suffered an ischemic stroke -- an attack caused by blocked blood flow to the brain. Fifty-eight of the patients were marijuana users.
The study couldn't prove that marijuana caused strokes, but Wolff's team did find some differences in stroke characteristics between pot users and non-users.
For example, a narrowing (stenosis) of the arteries in the skull was the cause of stroke in 45 percent of marijuana users, compared with only 14 percent of non-users, the findings showed.
Marijuana users with stroke were also younger, more likely to be male, more likely to also smoke cigarettes, and more likely to have other lifestyle risk factors than non-users, the research showed.
Blood clots that moved from other areas of the body to the brain were the most common cause of stroke (29 percent) in patients who did not use marijuana, compared with 14 percent in marijuana users, the investigators found.
The study appears in the Nov. 3 issue of the Journal of the American College of Cardiology. In a journal news release, editor-in-chief Dr. Valentin Fuster said that "the effects of cannabis have been considered benign for a long time; however, evidence continues to build about the relationship of its use with stroke."
Another expert agreed.
"This is an important study because it helps to change the public mindset about marijuana," said Dr. Richard Libman, vice chair of neurology at Long Island Jewish Medical Center in New Hyde Park, N.Y.
"Over the last few years, there have been numerous publications showing groups of young people, often teenagers, having strokes while smoking large quantities of marijuana," he said. "Almost definitely, marijuana is not as safe as many would like to think of it, including from the stroke standpoint."
The National Stroke Association has more about ischemic stroke.