The use of cannabis appears to contribute to a higher risk of myocardial infarction (MI) and stroke, with a similar but rising trend in ischaemic and haemorrhagic stroke, as shown by the results of a study presented at the AHA Scientific Sessions 2024c.

“Cannabis is among the most widely used psychotropic substances globally. With its increasing prevalence, questions have arisen regarding its potential impact on cardiovascular and cerebrovascular health,” said lead author Dr Vibhor Agrawal from King George’s Medical University in Lucknow, India.

In the past, many studies investigated the relationship between cannabis use and the risk of both cardiovascular and cerebrovascular diseases. However, the findings across these studies were inconsistent, according to Agrawal and colleagues, who then performed a meta-analysis that sought to explore the association between the use of cannabis and the risk of MI and stroke.

A systematic search was initially done using the databases of PubMed, Embase, and Scopus from inception to April 2024. Agrawal and his team looked for observational studies evaluating the association between cannabis use and events such as MI and stroke.

Two independent reviewers screened the identified studies, extracted the data, and assessed its quality. Pooled odds ratios (ORs) and 95 percent confidence intervals (CIs) were estimated through a random-effects meta-analysis, and heterogeneity was assessed via I2 statistic.

Twenty-six studies met the eligibility criteria, providing data for a total of 72,551,926 individuals, most of whom were female (69.5 percent). Among the participants, 7,832,105 (2.1 percent) were cannabis users (41.2 percent being female). [AHA 2024, abstract 4141299]

When compared with nonusers, users of cannabis were more likely to experience MI (OR, 1.38, 95 percent CI, 1.14?1.68) and stroke (OR, 1.43, 95 percent CI, 1.08?1.89).

For the stroke subtypes, a trend toward increased odds was observed for ischaemic stroke among cannabis users, but the difference did not reach statistical significance (OR, 1.60, 95 percent CI, 0.91?2.81). A similar trend was noted for the odds of haemorrhagic stroke, which also did not significantly differ from nonusers (OR, 1.98, 95 percent CI, 0.80?4.88).

“Our analysis reveals a significant increase in the odds of both MI and stroke in cannabis users. Notably, we observed a comparable yet increased trend in both ischaemic and haemorrhagic stroke subtypes,” Agrawal said. “Further research is crucial to delineate these associations and understand the underlying mechanisms.”

Survey data

These findings supported those of a survey conducted among 430,000 adults in the US, which found a link between cannabis use and a higher risk of heart attack and stroke. The odds were even greater among adults with more days of use per month. [https://newsroom.heart.org/news/cannabis-use-linked-to-increase-in-heart-attack-and-stroke-risk]

Additionally, smoking was the most common method of cannabis use, followed by eating and vaporizing. Of note, the increased risk of coronary heart disease, heart attack, and stroke was similar to that seen in adults who had never used e-cigarettes but did use cannabis.

“The perceptions of the harmfulness of smoking cannabis are decreasing, and people have not considered cannabis use dangerous to their health,” lead author Dr Abra Jeffers, a data analyst at Massachusetts General Hospital in Boston, Massachusetts, US, said in a press statement.

“However, previous research suggested that cannabis could be associated with cardiovascular disease. In addition, smoking cannabis?the predominant method of use?may pose additional risks because particulate matter is inhaled,” he added.