In the wake of a new study published on Sept. 7, a number of very troubling articles surfaced highlighting findings that suggest a correlation between cannabis use among young adults and what’s known as myocardial infarction. This fancy term for heart attacks was central to new research that appeared in the Canadian Medical Association Journal, which concluded that there was now “evidence supporting an association between recent cannabis use and history of MI in young adults.”
Given the popular prohibitionist stance that one reason to keep cannabis illegal is for the benefit of the children — a claim, it should be noted, that has continuously been refuted by hard science on multiple fronts — there was naturally a frenzy among mainstream media publications to paint a dire picture in light of this study’s findings.
“Young adult cannabis consumers nearly twice as likely to suffer from a heart attack, research shows,” warned CNN’s headline.
“Young adults using cannabis faced a 1.3% risk of heart attack history, compared to 0.8% of nonusers,” reads the subheadline of a similar article published by Fox News.
If true, such findings would absolutely be cause for alarm. Not even the staunchest advocates of cannabis reform would wish to ignore any comprehensive data suggesting that young adults who consume cannabis are at a statistically significant higher risk of suffering a heart attack. But there’s just one problem: the methodology and findings provided by this study are far from definitive proof of anything.
To be clear, what the study’s authors found certainly merits more research. However, the means by which they obtained these findings suggests an incomplete picture rather than one worthy of becoming instant alarm fodder for many of today’s most widely-read news organizations.
Writing for L.A. Weekly, veteran cannabis journalist Jimi Devine explained the limitations of the cross-sectional study employed by researchers to achieve their results.
“Cross-sectional studies, like this one,” he writes, “use data sets from population groups to figure stuff out in various fields whether it’s economics, other social sciences, or as in this case, medicine. The researchers, in this case, are using pooled data from the American Behavioral Risk Factor Surveillance System survey of U.S. adults from 2017 and 2018.”
The payoff of this effort is the following: of the 4,610 respondents who admitted to consuming cannabis, 61 (or 1.3%) also suffered heart attacks. By contrast, of the 28,563 respondents who claimed to be nonusers, only 240 (or 0.8%) reported an incident of myocardial infarction. Stated in simpler terms, this data suggests that young adults using cannabis are approximately 0.5% more likely to have a heart attack than nonusers — a fraction of a percentage, yes, but nonetheless a statistically significant conclusion.
So, what’s the problem? Devine reached out to NORML Deputy Director Paul Armentano to offer some vital context to these findings. One point of concern raised by Armentano is the inconsistencies between similar studies, an issue unquestionably exacerbated by the continued federal prohibition of cannabis and the limitations it subsequently places on scientific research on the subject.
“For instance,” Armentano noted, “longitudinal data conducted by the University of California finds no increased risk of adverse cardiovascular events in younger and middle-aged subjects with a history of cannabis use of several decades.”
Armentano also pointed to another study, this one population-based and published in 2021, which found that a history of cannabis use was actually associated with a decreased risk of adverse cardiovascular events once researchers put in controls to account for potential confounders. For clarity, confounders are external variables (like, in this case, smoking tobacco or drinking alcohol) that are not directly related to the thing being studied but may nonetheless have an impact on the results.
Further casting doubt on the empirical reliability of this new study was Morgan Fox, Media Relations Director for the National Cannabis Industry Association. Also queried by Devine for comment, Fox offered a frank assessment of why these new findings should be taken with a sizable grain of salt.
“This shows an association but not a causal relationship,” Fox asserted. “The sample size is extremely small, many of the products reported being used were unregulated, and the only strong correlation was with smoking as opposed to other forms of ingestion.”
Despite this undeniably stinging rebuke of a rush to paint cannabis as a potential heart attack risk to underage consumers, both Armentano and Fox agreed that more research is needed before any conclusions — positive or negative — are spoken of in definitive terms. In the meanwhile, however, mainstream media publications would clearly be well-advised to consider the concepts of nuance and context when covering such topics.
After all, being the first to publish is easy but getting it right is far more important.