Recent cannabis use tied to increased MI risk in young adults

Reuters Health - 07/09/2021 - Young adults who report recently using cannabis are twice as likely as those who do not to have a history of myocardial infarction (MI), according to a new study that found an especially strong association among frequent users.

Researchers analyzed 2017-2018 cross-sectional data from the U.S. Centers for Disease Control and Prevention (CDC) on a nationally-representative sample of more than 33,000 adults aged 18 to 44 years, of whom 17% said they had used cannabis in the past 30 days. After adjusting for a range of possible confounders, the study found cannabis users had 2.07 times the risk of MI compared with non-users, according to the results published in CMAJ.

"With recent decriminalization, and potential legalization at the federal level, cannabis use is increasing among young adults; and they should be aware of the cardiovascular risks associated with its use," said study coauthor Dr. David Mazer, a professor of anesthesia at St. Michael's Hospital, University of Toronto. "Our analysis is important because we provide insights which are representative and generalizable to this population. This information is important for both cannabis users and their healthcare providers," he added.

"We also observed that this association was consistent across different forms of cannabis consumption, including smoking, vaping, and other methods like edibles," Dr. Mazer said in an email. "Therefore, our study suggests that no method of consumption is safer than another with respect to this relationship. Heart attacks are very rare in young adults, and it is of concern that recent cannabis use may be a factor contributing to this risk."

It's not known exactly how cannabis might be linked to heart attacks, Dr. Mazer said.

"Cannabis has been shown to increase the heart's requirements for oxygen, while simultaneously inducing changes which impair the heart's ability to receive oxygen," he noted. "We think that the combination of these effects may result in a mismatch between oxygen supply to the heart and the amount of oxygen needed to maintain its healthy function, ultimately resulting in a heart attack."

To take a closer look at possible links between cannabis use in young adults and heart attack risk, Dr. Mazer and his team analyzed data collected from two cycles of the annual Behavioral Risk Factor Surveillance System telephone survey conducted by the CDC. The survey collects data on risk behaviors, chronic health conditions, and use of preventive services.

Included in the analysis were data from 33,173 young adults (representing 18.5 million weighted). Of these, 4,610 reported they had recently used cannabis and 28,563 reported no cannabis use.

Recent cannabis users, compared with non-users, were more commonly males (62.9% versus 49.3%), unmarried (68.0% versus 46.4%), current users of traditional cigarettes (31.6% versus 13.2%) and e-cigarettes (18.1% versus 5.1%), and heavy alcohol drinkers (17.4% versus 5.2%).

Most cannabis users (70.5%) reported frequent cannabis use, meaning more than four times during the past 30 days. Smoking was the most common primary method of cannabis consumption (76.3%) relative to vaporization (11.3%), and other forms of consumption, including edibles (12.4%).

A history of MI was reported by 61 cannabis users (1.3%) and 240 of the non-users (0.8%). After adjusting for demographic and socioeconomic factors, health behaviors such as insurance coverage, comorbidities, and concomitant substance use, cannabis users were more likely to have a history of MI (adjusted odds ratio 2.07) than non-users. The association was stronger among frequent cannabis users (aOR, 2.31) than less-frequent users (aOR 1.48).

Edibles and "other" forms of consumption were associated with the highest risk (aOR 2.36) relative to non-users, followed by vaporization (aOR 2.26), though these were not statistically significant, the authors note. Smoking cannabis as the primary means of consumption was significantly associated with a history of MI (aOR 2.01).

"This study adds insight into the possible associations between cannabis use and adverse cardiovascular outcomes, specifically a history of myocardial infarction (MI) in younger people, a population that is not usually at high risk for these events," said Ziva Cooper, an associate professor at the Jane and Terry Semel Institute for Neuroscience and Human Behavior at the David Geffen School of Medicine at the University of California, Los Angeles, and director of the UCLA Cannabis Research Initiative.

"Importantly, the frequency of these events increased with more frequent cannabis use and in people who reported primarily smoking cannabis rather than using other forms like vaporizing or edible use," Cooper said in an email. "Because the analysis assesses history of MI, it is unknown what people's pattern of cannabis use and other substance use was like at the time of the event," she noted.

"It is also unknown how exposure to delta-9-THC, the primary chemical in the cannabis plant thought to contribute to these cardiac events, was associated with increased frequency of MI history," said Cooper, who was not involved in the research. "As cannabis availability and use continues to increase nationally and internationally, it is critical to explore variables that may contribute to cannabis-associated negative cardiac events, including frequency of use, co-use of other substances, ways in which people are using cannabis (smoking versus vaporizing versus oral use), and exposure to different cannabis constituents that are emerging in the marketplace including CBD, delta-8-THC, and others."

SOURCE: https://bit.ly/3DOdzLb CMAJ, online September 7, 2021.

By Linda Carroll



Posted on 7 September 202115 September 2021