Cannabis use tied to elevated heart attack risk in younger adults

ByKatie Kalvaitis

Fact checked byRichard Smith

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Key takeaways:

Cannabis users aged 50 years and younger were six times as likely to have a heart attack vs. nonusers.
Researchers said further research is needed to confirm the results.

New research links regular cannabis use with heart attack and other adverse cardiovascular events in otherwise healthy adults aged 50 years and younger.

The findings come from a retrospective study of more than 4.6 million people and a meta-analysis of 12 previously published studies, both slated for presentation at the American College of Cardiology Scientific Session.

“Clinicians should actively screen for cannabis use in patients, provide appropriate counseling and recognize that cannabis is not as benign as commonly perceived. Its cardiovascular risks warrant further clinical attention and patient education,” Ibrahim Kamel, MD, MHA, clinical instructor at Boston University Chobanian & Avedisian School of Medicine and internal medicine resident at St. Elizabeth Medical Center, told Healio.

Evaluating long-term CV effects

Cannabis has therapeutic benefits, but its use has been linked to adverse CV outcomes in prior research, the researchers wrote in JACC: Advances. However, the long-term effects of cannabis use are not fully understood, in part due to confounding factors such as tobacco use and established CV risk factors, according to the researchers.

Kamel and colleagues looked specifically at long-term CV effects of regular cannabis use among younger, relatively healthy adults without traditional CV risk factors. The researchers analyzed data from the TriNetX health research network on more than 4.6 million adults aged 50 years and younger from 2010 to 2018. Of those, 2% were cannabis users, with cannabis-use diagnoses, and 98% reported no cannabis use. Both groups were free of major comorbidities at baseline, including hypertension, hyperlipidemia, CAD including previous MI or coronary intervention, diabetes and tobacco use. Those who used cannabis were older (26 years vs. 21 years), had a higher prevalence of depressive episodes (30.63% vs. 1.88%) and BMI more than 30 kg/m² (18.72% vs. 3.25%).

The primary outcome was MI.

During an average follow-up of 3 years, those who reported cannabis use had a more than sixfold higher risk for MI (OR = 6.214), fourfold higher risk for ischemic stroke (OR = 4.347), threefold higher risk for CV death, MI or stroke (OR = 3.267) and twofold increased risk for HF (OR = 2.038) compared with those who did not use cannabis, according to the results.

“Our study provides strong evidence of increased cardiovascular risk associated with cannabis use, even in well-balanced cohorts. We demonstrate a clear association between cannabis consumption and multiple adverse cardiovascular outcomes, reinforcing the need for greater awareness of its potential dangers,” Kamel told Healio.

New meta-analysis

Kamel and colleagues also performed a meta-analysis using data from 12 studies that involved more than 75 million participants. Ten of the studies were conducted in the United States. The average age of participants was 41 years across the studies that reported information on age, according to a press release issued by the ACC.

This is the largest pooled study, to date, on cannabis use and MI, according to the researchers.

In seven studies, researchers reported a significant positive association between cannabis use and the incidence of MI. One study demonstrated a negative association between cannabis use and MI. Four studies found no association, according to the release.

However, when data from all 12 studies were pooled, the researchers reported a significant positive association between cannabis use and MI. In particular, people who reported active cannabis use were 1.5 times more likely to have an MI compared with those who did not use cannabis, according to the release.

‘Unexpected finding’

“Our research was inspired by a case we encountered in the ED — a previously healthy 23-year-old male who presented with nausea. Routine testing revealed significantly elevated troponins (> 1,000), prompting urgent cardiac catheterization. He was found to have a thrombotic coronary lesion, which was successfully treated with angioplasty and stenting. Despite extensive investigation, common risk factors and etiologies for myocardial infarction were ruled out. However, further history revealed that the patient had consumed cannabis just hours before symptom onset.

“This unexpected finding led us to explore whether cannabis use could be an independent risk factor for myocardial infarction,” Kamel told Healio.

Limitations, future research

“The most surprising aspect of our findings is the significant and potentially severe cardiovascular risk posed by cannabis use. While cannabis is often perceived as harmless, our data suggest that its use may contribute to major adverse cardiac events, including myocardial infarction, even in young and otherwise healthy individuals,” Kamel told Healio.

The researchers said their findings are consistent with previous research that demonstrates increased risk for ACS after cannabis use.

“Studies suggest that cannabis use can precipitate MI, particularly within an hour of consumption, with the risk increasing nearly fivefold. This effect is pronounced in young, healthy individuals, who present with chest pain. Cannabis has also been implicated in endothelial dysfunction, pro-inflammatory cytokine release and oxidative stress, all of which contribute to coronary microvascular dysfunction and plaque destabilization,” the researchers wrote in JACC: Advances.

There are several limitations of the retrospective study and meta-analysis. The researchers cited inconsistent patient reporting and a lack of detailed data on cannabis consumption and type of cannabis consumed. They also could not account for potential confounding factors such as duration and amount of cannabis and concomitant use of tobacco and/or other drugs.

Future research should include mechanistic bench studies with invasive arterial flow measurements to gain a better understanding of cannabis-induced vascular effects, Kamel told Healio. Randomized controlled trials are also needed “to establish causality and further clarify the extent of cardiovascular risk,” Kamel told Healio.