Cannabis linked to strokes - study
Young adults who smoke cannabis are twice as likely to have a stroke than non-smokers, a University of Auckland study has shown.
Researchers at the university's Centre for Brain Research made the discovery while studying 160 stroke patients.
It showed patients suffering stroke and transient ischemic attack, where blood flow to the brain is temporarily restricted, were 2.3 times more likely to have cannabis detected in urine tests than others of the same age and gender.
Professor Alan Barber, lead investigator for the study, said this was the first case-controlled study to show a possible link between cannabis and an increased stroke risk.
"Cannabis has been thought by the public to be a relatively safe, although illegal, substance," he said. "This study shows this might not be the case, it may lead to stroke."
Of the 160 patients, 16 per cent tested positive for cannabis. Researchers also found positive testing patients were mostly male and also smoked tobacco.
There were no differences in age, stroke type or most vascular risk factors between cannabis users and non-users.
Barber said researchers hoped to do another study to determine if there was an association between cannabis and stroke, independent of tobacco use.
All but one of the stroke patients who were cannabis users also used tobacco regularly which had brought further questions.
"The high prevalence of cannabis use in this cohort of younger stroke patients makes this research imperative.
"We believe it is the cannabis use and not tobacco."
Barber said physicians should test young people who come in with stroke symptoms for cannabis use.
"People need to think twice about using cannabis, because it can affect brain development and result in emphysema, heart attack and now stroke," he said.
The findings were presented to the American Stroke Association's International Stroke Conference 2013 in Honolulu this week.