Smoking cannabis nearly doubles the risk of a heart attack in adults under the age of 45, study suggests
- Canadian researchers looked at history of heart attacks in 33,000 adults 18 to 45
- One in five reported using cannabis and twice as likely to have had heart attack
- 1.3% of cannabis users had suffered heart attack, compared to 0.8% of non-users
Smoking cannabis nearly doubles the risk of young adults suffering a heart attack, a study has suggested.
Canadian researchers looked at the history of heart attacks in more than 33,000 adults aged 18 to 44.
Nearly one in five of these young adults reported using cannabis – and this group were twice as likely to have suffered a heart attack.
Overall 1.3 per cent of cannabis users had experienced a heart attack, compared to 0.8 per cent of non-users.
Heart attacks were most common in those who took cannabis at least once a week, and the risk was the same regardless of if it was consumed through smoking, e-cigarettes or edibles.
Smoking cannabis nearly doubles the risk of young adults suffering a heart attack, a study has suggested (stock)
The scientists from the University of Toronto called on young adults to be aware of the risks of the drug, and said it shows the potentially dangerous consequences of legalising cannabis use.
Cannabis has been legalised in several US states, and some MPs have backed a similar move in the UK.
Warning for edible cannabis users: Doctors say they take longer to give a high and can interact with alcohol, sleeping pills and opioids
Cannabis users should be wary of the hidden dangers when using edibles, top doctors have warned.
Tea, cakes, chocolate and sweets infused with the drug are commonly viewed as a safer alternative to smoking or vaping.
But they can render users unconscious, make them sick or trigger paranoia if taken alongside alcohol, sleeping pills or opioids, health experts say.
The warning was issued by doctors in Canada weeks after the country legalised cannabis edibles, allowing shops to stock the products on their shelves.
Ingested marijuana takes four or more hours to give users a ‘high’, but the effects are more intense and can last up to eight hours.
This is far slower than smoked or vaped cannabis, which normally takes effect within a matter of minutes.
Users who still feel sober hours after consuming edibles may be tempted to take more because they think they don’t work, doctors from the University of Toronto say.
This increases the risk of taking more than they can handle and having an unpleasant experience.
Dr Jasleen Grewal and Lawrence Loh warned ‘cannabis naive’ people were at risk in a commentary in the Canadian Medical Association Journal.
They urged users to keep products out of reach of children and pets because many edibles look like candy and other appetising food and drink.
But the drug is linked to mental illness and there is now also mounting evidence to show it can damage the heart.
Study author Dr Karim Ladha said: ‘With recent legalisation and decriminalisation, cannabis use is increasing in young adults in North America, and we do not fully know its effects on cardiovascular health.
‘We found an association between recent cannabis use and heart attack, this association was consistent across different forms of cannabis consumption, including smoking, vaporisation, and other methods such as edibles.
‘This suggests that no method of consumption is safer than another in this regard.’
Co-author Dr David Mazer said: ‘Not only young adults, but physicians and other clinicians need to be aware of this potentially important relationship.
‘Cannabis use should be considered in cardiovascular risk assessment.
‘When making decisions about cannabis consumption, patients and physicians should consider its associated benefits and risks, in the context of their own health risk factors and behaviours.’
The observational study could not establish if cannabis played a role in the heart attacks, but the expert pointed to previous research showed the drug can affect a user’s heart rate.
Dr Ladha said that when a heart rate becomes irregular, it can limit the amount of oxygen delivered to the heart.
But critics say cannabis may not be the underlying cause in heart attack patients. Users are more likely to drink heavily and smoke tobacco – both habits are known to raise the risk of heart complications.
Previous research has suggested that regular users of cannabis are more likely to have structural damage to the heart which may increase their risk.
Scientists from Queen Mary University of London analysed MRI scans from 3,407 people in the UK Biobank in 2019.
They found that smokers were more likely to have an enlarged left ventricle, the heart’s main pumping chamber.
As its walls get thicker less blood is able to be transported around the body, which experts say can increase the risk of strokes.
The study found regular cannabis smokers also had impaired heart function, with tests showing their muscle fibres deforming whenever their hearts contracted.