Cannabis use is linked to a doubling in the risk of dying from cardiovascular disease, with significantly heightened risks of having a stroke or acute coronary syndrome—sudden reduced or blocked blood flow to the heart—finds a pooled analysis of real world data, published online in the journal Heart.
The authors of a linked editorial call for the drug to be treated like tobacco—not criminalised, but actively discouraged, with protection of bystanders from secondhand vapour inhalation.
The use of cannabis and cannabinoids has soared over the past decade, note the researchers. Legalising cannabis in certain jurisdictions and expanding its use for medicinal purposes has probably changed people's risk perceptions of the drug and helped drive its growing popularity, they suggest.
While previously published studies have linked cannabis use to cardiovascular problems, the magnitude of the risk hasn't been clear. This is an important gap in light of the recent major changes in consumption and the increased potency of the drug, they add.
To strengthen the evidence base, therefore, the researchers scoured research databases looking for large observational studies, published between January 2016 and December 2023, which explored cannabis use and serious cardiovascular outcomes: cardiovascular disease death; and non-fatal acute coronary syndrome to include heart attack and stroke.
From an initial haul of 3012 articles, 24, involving around 200 million people, were included in a pooled data analysis of the results: 17 cross-sectional studies, 6 cohort studies, and 1 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 researchers acknowledge that 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. And most of the included studies were observational, precluding the ability to draw causal inferences from the data. Several used the same data.
Notwithstanding these caveats, the researchers say that theirs is an exhaustive analysis of published data on the potential association between cannabis use and major cardiovascular disease and provides new insights from real-world data.
In a linked editorial, Emeritus Professor Stanton Glantz of the University of California at San Francisco and Dr Lynn Silver of the Public Health Institute, Oakland, California, and Department of Epidemiology and Biostatistics, University of California at San Francisco, say the study "raises serious questions about the assumption that cannabis imposes little cardiovascular risk."
More research is clearly needed to clarify whether cardiovascular risks are limited to inhaled products or extend to other forms of cannabis exposure, they suggest. 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 point out.
"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," they say.
They conclude: "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."
