Cannabis use could double risk of heart deaths, study suggests

Cannabis use may double the risk of dying from heart disease and increase the risk of stroke by 20%, according to a global review of data.

The number of people using cannabis and cannabinoids has soared over the past decade. While previous studies have linked cannabis use to cardiovascular problems, the scale of the risk has until now not been clear.

This is an important gap in light of major changes in consumption, researchers at the University of Toulouse in France said.

To strengthen the evidence base, they searched databases looking for large observational studies, published between 2016 and 2023, which explored cannabis use and cardiovascular outcomes.

Twenty-four studies, involving about 200 million people, were included in a pooled data analysis of the results: 17 cross-sectional studies, six cohort studies, and one case-control study.

Study participants were mostly aged between 19 and 59. And in those studies where sex was recorded, cannabis users tended to be mostly male and younger than non-users.

The analysis revealed heightened risks for cannabis use: 29% higher for acute coronary syndrome; 20% higher for stroke; and a doubling in the risk of dying from cardiovascular disease. The findings were published in the journal Heart.

The researchers acknowledged several limitations to their systematic review and meta analysis. There was a moderate to high risk of bias in most of the included studies, largely because of lack of information on missing data and imprecise measures of cannabis exposure. Most of them were observational and several used the same data.

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With these caveats, the researchers said their work was an exhaustive analysis of published data on the potential association between cannabis use and major cardiovascular disease and provided new insights from real-world data. “The findings outlined by this meta analysis should enhance the general awareness of the potential of cannabis to cause cardiovascular harm.”

In a linked editorial, Prof Stanton Glantz and Dr Lynn Silver of the University of California at San Francisco said the analysis “raises serious questions about the assumption that cannabis imposes little cardiovascular risk”.

More research is needed to clarify whether cardiovascular risks are limited to inhaled products or extend to other forms of cannabis exposure, they said. Cannabis is now generally more potent and has diversified into a wide array of inhaled high potency cannabis concentrates, synthetic psychoactive cannabinoids, and edibles, they added.

They wrote: “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 needs to be incorporated into the framework for prevention of clinical cardiovascular disease. So too must cardiovascular disease prevention be incorporated into the regulation of cannabis markets. 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.

“Specifically, cannabis should be treated like tobacco: not criminalised, but discouraged, with protection of bystanders from secondhand exposure.”