But US experts say legalise it, discourage it and “treat it like tobacco” after global review of 200 million cannabis users
Smoking cannabis could double the risk of dying from a heart attack or stroke, research suggests. A huge review of international observational studies shows people who use, or have previously used the recreational drug are more likely to go on to have heart problems.
Experts say the findings cannot prove definitively that it is the cannabis compound causing heart problems but that the public should be warned it is possible. US researchers carried out the review of 24 studies covering 200 million people which concluded cannabis use was linked to twice the risk of dying from cardiovascular disease in some way, such as by heart attack or stroke.
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Commenting on the study, Professor Stanton Glantz, of the University of California in the US, said: “This study raises serious questions about the assumption that cannabis imposes little cardiovascular risk.
How these changes affect cardiovascular risk requires clarification, as does the proportion of risk attributable to cannabinoids themselves versus particulate matter, terpenes or other components of the exposure.”
Cannabis has consistently been the most used illegal drug in Britain since records began in 1995. Latest data from the Office for National Statistics showed 7% of adults aged 16 to 59 used it last year. Among 16 to 24 year olds it was 14%.
The review, by the University of Toulouse in France, included observational studies and population research conducted between 2016 and 2023. Those studies were mostly aged between 19 and 59 and showed cannabis users tended to be “mostly male” and younger on average than non-users.
The findings, published in the medical journal Heart, showed a doubling of the chance of current or former cannabis users going on to die where the cause of death was listed as heart disease. They also had a 20% higher risk of non-fatal stroke.
It comes after a number of countries have started to legalise and tightly regulate recreational cannabis use such as Canada, Germany, Luxembourg, Malta, Mexico, South Africa and Thailand.
Author Dr Emilie Jouanjus, of the University of Toulouse, legalisation and expanding its use for medicinal purposes may have “changed people’s risk perceptions” of the drug and helped drive its growing popularity globally.
She said: “While recreational cannabis is illegal and strictly regulated, nevertheless, its use is among the most prevalent in Europe, especially in the young. Legalising the drug and expanding its medical use worldwide have likely contributed to profound changes in the general perception of cannabis and to the overall rise in cannabis consumption.
“Our findings are consistent with those from previous reviews, which outlined a positive association between cannabis use and cardiovascular disorders. The increased awareness of this potential risk among cannabis users should encourage investigating such use in all patients presenting with serious cardiovascular disorders.”
In his linked editorial, Professor Glantz, who was not involved in the research, called on cannabis to be legalised but “treated like tobacco”. He added: “Effective product warnings and education on risks must be developed, required, and implemented.
Cardiovascular and other health risks must be considered in the regulation of allowable product and marketing design as the evidence base grows. Today that regulation is focused on establishing the legal market with woeful neglect of minimising health risks.
“Cannabis should be treated like tobacco: not criminalised, but discouraged, with protection of bystanders from secondhand exposure.”