Marijuana Use May More than Double the Risk of Stroke in Young Adults
Here's another study that will certainly add fuel the ferocious marijuana debate: health researchers found that smoking pot could more than double the risk of stroke in young adults. However, experts were quick to point out that the latest study, presented Wednesday at the International Stroke Conference, was small and inconclusive.
The New Zealand study found that people between the age of 18 and 55 who had experienced a stroke were 2.3 times more likely to test positive for marijuana in their urine compared to those who never had a stroke.
While the study doesn't prove for sure that smoking marijuana triggers strokes, the findings does provide strong evidence that a lifestyle that includes cannabis use is closely associated with a doubling of stroke risk, researchers said.
"This is the first case-controlled study to show a possible link to the increased risk of stroke from cannabis," said lead author Dr. Alan Barber, a stroke neurologist and professor of clinical neurology at the University of Auckland in New Zealand, according to a news release.
"Cannabis has been thought by the public to be a relatively safe, although illegal substance. This study shows this might not be the case; it may lead to stroke," he added.
The study included 160 stroke patients and 160 healthy participants who were all between the ages of 18 and 55, an age range in which people rarely suffer a stroke, according to researchers.
Researchers said that among the stroke patients, 150 were admitted to the hospital for an ischemic stroke, the most common type of stroke where blood flow is blocked to the brain. The other 10 patients had been admitted to the hospital for a transient ischemic attack (TIA or "mini-stroke").
The study revealed that while 16 percent of the patients tested positive for marijuana, only 8 percent of the healthy participants tested positive for pot use.
Researchers noted that they found no difference in age, stroke mechanism or most vascular risk factors between marijuana users and non-users.
Barber also noted that in previous case reports, ischemic stroke and TIAs developed hours after pot use.
"These patients usually had no other vascular risk factors apart from tobacco, alcohol and other drug usage," he said.
Researchers said that the latest study provided the "strongest evidence to date" that linked pot use to stroke. However, they noted that the association is somewhat confounded because all but one of the stroke patients who were marijuana users also used tobacco on a regular basis.
"We believe it is the cannabis and not tobacco," said Barber, who plans to conduct an additional study to determine whether there is a link between cannabis and stroke independent of tobacco use.
"This may prove difficult given the risks of bias and ethical strictures of studying the use of an illegal substance," he said. "However, the high prevalence of cannabis use in this cohort of younger stroke patients makes this research imperative."
Barber told HealthDay that he thinks the relationship between pot use and stroke is "certainly plausible".
"We know [from other studies] cannabis reduces the time to angina, that it's associated with myocardial infarction [heart attack] and heart rhythm problems. It can also cause vasoconstriction. If you constrict arteries in the brain, you can have reduced blood flow," he said, according to HealthDay.
"We believe the association is not just a chance one, but worthy of further investigation," Barber said.