Cannabis smokers may be two-and-a-half times more likely to suffer a stroke ‘because compounds in the drug can narrow blood vessels in the brain’
- Stroke increased 2.5 times for people who smoked cannabis three times a week
- Users who also smoked cigarettes or vaped saw stroke risk spike by three-fold
- Researchers say doctors must warn cannabis smokers of this risk in future
Smoking cannabis more than doubles your chance of suffering a stroke, a new study has found.
Researchers looked at more than 40,000 adults aged between 18 and 44 over a year-long period.
They found those who used cannabis more than three times a week were two-and-a-half times more likely to have a stroke compared to non-smokers.
Cannabis users who also smoked cigarettes or used vape products had triple the risk compared to non-users.
The finding adds to a growing body of evidence that links cannabis use to the life-threatening condition.
Smoking cannabis more than doubles your chance of suffering a stroke, according to new research from the George Mason University in Fairfax, Virginia
Scientists say smokers should be made aware of this risk by their doctors, especially as the drug becomes more accessible in a growing number of states.
Previous research has shown compounds known as cannabinoids in cannabis may cause blood vessels in the brain to narrow, triggering a stroke.
Eleven US states have already legalised the recreational use of marijuana, including California, Colorado and Massachusetts.
Cannabis can also be taken for medical reasons in 21 additional states, such as Illinois, Florida and Pennsylvania.
The latest study, by the George Mason University in Fairfax, Virginia, analysed 43,000 adults between 2016/17.
Nearly 14 per cent of participants reported using cannabis in the last 30 days.
Compared with non-users, marijuana smokers were often younger, less likely to be college graduates and often physically active.
Cannabis users were also more likely to be heavy drinkers and smoke cigarettes or vape, the researchers found.
This may have also influenced their risk, even though the team adjusted for those factors in their analysis.
The study was observational and did not examine why smoking cannabis may cause strokes.
Lead study author Tarang Parekh said: ‘Young cannabis users, especially those who use tobacco and have other risk factors for strokes, such as high blood pressure, should understand that they may be raising their risk of having a stroke at a young age.
‘Physicians should ask patients if they use cannabis and counsel them about its potential stroke risk as part of regular doctor visits.’
The study is published in Stroke, a Journal of the American Stroke Association, a division of the American Heart Association (AHA).
Robert Harrington, president of AHA and professor of medicine at Stanford University in California, said: ‘As these products become increasingly used across the country, getting clearer, scientifically rigorous data is going to be important as we try to understand the overall health effects of cannabis.’
Stroke is the second leading cause of death and disability globally, with one person passing away from the condition every six seconds.
Around 140,000 people die from stroke in the US and 32,000 in the UK every year.
It comes after two cannabis-based medicines were made available on the NHS for children.
Youngsters with two rare life-threatening forms of epilepsy will now have access to the drug Epidyolex, which helps to reduce seizures.
And patients with multiple sclerosis (MS) will be offered a cannabis-based spray called Sativex which is used to treat muscle stiffness and spasms.
It is the first time drugs containing cannabis have been recommended for NHS use by the drugs watchdog NICE.