Cannabis Linked to 2x Risk of Heart Disease Death, Scientists Discover

New research suggests that cannabis use is linked to twice the risk of death from cardiovascular disease, and is also associated with increased risk of other major adverse cardiovascular events (MACE).
Cannabis is being legalized in more and more places worldwide, increasing medicinal and recreational use – but it may warrant closer monitoring by health professionals. The researchers here, led by a team from the University of Toulouse in France, wanted to look more closely at potential health risks that had previously been flagged.
They looked at 24 previous studies published between 2016 and 2023, involving around 200 million people. Overall, the increased risk linked to cannabis use was 29 percent for acute coronary syndrome (reduced blood flow to the heart), 20 percent for strokes, and 100 percent for cardiovascular disease mortality.
"The findings reveal positive associations between cannabis use and MACE," write the researchers in their published paper. "These findings should encourage investigating cannabis use in all patients presenting with serious cardiovascular disorders."
There are some limitations worth bearing in mind here. The studies included in the research differed in terms of how they defined cannabis use, relied on self-reporting, and didn't measure use of the drug over time. That makes them less statistically robust.
The research also notes a high risk of bias in the majority of studies investigated, due to the way they were structured.
And it's important to say the research doesn't show direct cause and effect, only an association. It's possible that other factors not considered here are driving both cannabis use and heart health issues in certain groups of people.
Nevertheless, the large number of people surveyed on their real-world use of cannabis counts in the study's favor. It also has more recent data than many other studies, and we know that cannabis use and composition is changing over time.
That's enough to warrant deeper investigation into the possible health risks.
"Legalizing 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," write the researchers.
"Consequently, users' profiles and consumption habits profoundly differ from those in the 2010s, especially as cannabis products show an increasing trend in potency, with rising concentrations of delta-9-tetrahydrocannabinol (THC)."
Further research is absolutely needed here, not least to determine whether the chemicals and compounds in cannabis – of which there are hundreds – could be leading to these health risks, and how taking cannabis in different forms, such as inhalables or edibles, might have an influence.
Previous studies have already shown how the drug can increase the risk of cancer, and significantly alter our DNA, for example. Cannabis could also trigger psychosis through the impact it has on the brain.
The new study is accompanied by an editorial written by epidemiologists Stanton Glanz and Lynn Silver, from the University of California San Francisco. In it, Glanz and Silver argue that as cannabis use rises, more should be done to educate people about the risks – as has been done with cigarettes.
"Specifically, cannabis should be treated like tobacco: not criminalized but discouraged, with protection of bystanders from secondhand exposure," they write.
The research has been published in the journal Heart.
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Novo Nordisk A/S: CagriSema 2.4 mg / 2.4 mg demonstrated 22.7% mean weight reduction in adults with overweight or obesity in REDEFINE 1, published in New England Journal of Medicine

Data presented simultaneously at the American Diabetes Association's® 85th Scientific Sessions, showed mean weight reduction in the highest range of efficacy observed with existing weight loss interventions1 When adhering to treatment, weight loss of ≥5%, ≥20%, ≥25%, and ≥30% was observed in 97.6%, 60.2%, 40.4% and 23.1% of patients respectively at 68 weeks1* The REDEFINE clinical programme is ongoing to further investigate efficacy and safety of CagriSema, including recently initiated REDEFINE 112 Bagsværd, Denmark, 22 June – Today, The New England Journal of Medicine (NEJM) published results from Novo Nordisk's phase 3 REDEFINE 1 trial evaluating the efficacy and safety of investigational CagriSema plus lifestyle interventions for weight loss in adults with obesity or overweight who have a weight-related medical complication and without diabetes.1 REDEFINE 1 met its co-primary endpoints and achieved statistically significant and clinically meaningful weight loss at 68 weeks in patients taking CagriSema versus placebo.1 These data, along with the related phase 3 REDEFINE 2 study conducted in adults with overweight or obesity and type 2 diabetes, were presented today during a scientific symposium at the American Diabetes Association's (ADA) 85th Scientific Sessions and published in NEJM. 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About the REDEFINE clinical trial programmeREDEFINE is a phase 3 clinical development programme with once-weekly subcutaneous CagriSema in obesity. REDEFINE 1 and REDEFINE 2 have enrolled approximately 4,600 adults with overweight or obesity. REDEFINE 1 was a double-blind, placebo-and active-controlled 68-week efficacy and safety phase 3 trial of once-weekly CagriSema, cagrilintide 2.4 mg and semaglutide 2.4 mg versus placebo in 3,417 adults with obesity or overweight with one or more comorbidities and without type 2 diabetes. REDEFINE 2 was a double-blind, randomized, placebo- and controlled 68-week efficacy and safety phase 3 trial of once-weekly CagriSema versus placebo in 1,206 adults with type 2 diabetes and either obesity or overweight. Multiple REDEFINE clinical trials are currently underway including: REDEFINE 3, an event-driven cardiovascular outcomes phase 3 trial; REDEFINE 4 an 84-week head-to-head efficacy and safety phase 3 trial of once-weekly CagriSema versus once-weekly tirzepatide; and REDEFINE 11, a phase 3 trial with longer duration and other protocol changes compared to REDEFINE 1 and 2. About obesity Obesity is a serious chronic, progressive, and complex disease that requires long-term management.4-6 One key misunderstanding is that this is a disease of just lack of willpower, when in fact there is underlying biology that may impede people with obesity from losing weight and keeping it off.4,6 Obesity is influenced by a variety of factors, including genetics, social determinants of health, and the environment.7,8 Novo Nordisk is a leading global healthcare company founded in 1923 and headquartered in Denmark. Our purpose is to drive change to defeat serious chronic diseases built upon our heritage in diabetes. We do so by pioneering scientific breakthroughs, expanding access to our medicines, and working to prevent and ultimately cure disease. Novo Nordisk employs about 77,400 people in 80 countries and markets its products in around 170 countries. For more information, visit Facebook, Instagram, X, LinkedIn and YouTube. Contacts for further information Media: Ambre James-Brown +45 3079 9289 abmo@ Liz Skrbkova (US) +1 609 917 0632 lzsk@ Investors: Jacob Martin Wiborg Rode +45 3075 5956 jrde@ Ida Schaap Melvold +45 3077 5649 idmg@ Sina Meyer +45 3079 6656 azey@ Max Ung +45 3077 6414 mxun@ Frederik Taylor Pitter +1 609 613 0568 fptr@ References: Garvey WT, Blüher MD, Contreras CKO, et al. CagriSema in Adults with Overweight or Obesity. New England Journal of Medicine 2025. doi: 10.1056/NEJMoa2502081 A Research Study to Look at How Well CagriSema Helps People Living With Obesity Lose Weight and Maintain Weight Loss in the Long-term. Last Accessed: June 2025. Available at: Davies MJ, Harpreet S, Bajaj MD, et al. CagriSema in Adults with Overweight or Obesity and Type 2 Diabetes. New England Journal of Medicine 2025. Kaplan LM, Golden A, Jinnett K, et al. Perceptions of barriers to effective obesity care: results from the national action study. Obesity. 2018;26(1):61-69. Bray GA, Kim KK, Wilding JPH; World Obesity Federation. Obesity: a chronic relapsing progressive disease process. A position statement of the World Obesity Federation. Rev. 2017;18(7):715-723. Garvey WT, Mechanick JI, Brett EM, et al. American association of clinical endocrinologists and American College of Endocrinology comprehensive clinical practice guidelines for medical care of patients with obesity. Endocr Pract. 2016;22 (Suppl 3):1-203. Centers for Disease Control and Prevention. Adult obesity facts. Last accessed: June 2025. Available at: World Obesity Federation. World Obesity Atlas 2023. Last accessed: June 2025. Available at: Attachment PR250622-ADA-CagriSema

CNN

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How your AI prompts could harm the environment

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