Two recent studies have found that daily cannabis use may be correlated to increased risk of heart failure or cardiac events. Many studies that highlight the so-called dangers of marijuana are often plagued by shady funding, conflicts of interest and poor research. Are these any different? Here’s what you need to know:
Although cannabis has been shown to be an effective treatment for a number of ailments, scientists have only begun to scratch the surface when it comes to knowing exactly what it does to the body. While studies funded by the National Institute on Drug Abuse (NIDA) or the Drug Enforcement Administration (DEA) can be taken with a grain of salt due to those agencies’ inherent biases, presumably, the American Heart Association (AHA) should be a trustworthy source with no reason to push for an agenda.
But the AHA does receive funding from a number of corporate and pharmaceutical interests that could have motive to undermine weed’s popularity as a medicine, and the two studies haven’t escaped some criticism.
Both studies were presented at the recent AHA Scientific Sessions in Philadelphia.
Study One
“Prior research shows links between marijuana use and cardiovascular disease like coronary artery disease, heart failure and atrial fibrillation, which is known to cause heart failure,” said the lead author of the first study, Yakubu Bene-Alhasan, in an AHA news release. “Marijuana use isn’t without its health concerns, and our study provides more data linking its use to cardiovascular conditions.”
Bene-Alhasan’s team gathered surveys from 156,999 individuals about the frequency of their marijuana use. All of the participants were free of heart disease when they began taking the surveys and researchers took demographic, economic factors, alcohol use, smoking and other cardiovascular risk factors into account while analyzing the data.
The team followed the participants for four years. During that time, 2,958 of the participants suffered heart failure (1.9 percent of the group). Those who reported daily marijuana use were 34 percent more likely to have suffered heart failure, compared to those who reported never using weed.
In a secondary analysis, the researchers added coronary artery disease and the risk of heart failure dropped from 34 percent to 27 percent. The researchers said the data suggests that coronary artery disease might be correlated with daily marijuana use.
The study relied on self-reporting, which is known to be unreliable. But in this instance it may not be quite the silver bullet some may be hoping for, since there was little risk or reward involved with choosing whether to be honest about weed use.
The data was collected from the National Institutes of Health’s (NIH) All of Us Research Program. The NIH has a reciprocal relationship with a number of Big Pharma companies, which, in turn, would have a vested interest in stomping out any competing medical treatments. But as with self-reporting, this isn’t quite the damning piece of evidence that some may believe it is—it’s just something to keep in mind.
However, the paper has not been peer-reviewed or published, and only the abstract is available, meaning the authors’ methods and analysis are still a mystery.
Most notable of all, is its misleading use of percentages. The study says weed users had a 34 percent higher chance of developing heart failure compared to non-users. Since 34 percent of 1.9 percent (the group heart failure rate) is around 0.65 percent, that means daily cannabis users had only a 2.55 percent chance of developing heart failure altogether—a much less frightening number when put in perspective.
Study Two
For the second study presented at the sessions, researchers analyzed data from the 2019 National Inpatient Sample. It’s the largest, publicly available, all-payer inpatient healthcare database in the nation, sponsored by the Department of Health and Human Services (HHS).
The researchers looked at whether hospital stays were complicated by a cardiovascular event like heart attack, stroke, cardiac arrest or arrhythmia. Records on adults older than 65 years with existing cardiovascular risk factors like high blood pressure, Type 2 diabetes or high cholesterol who reported no tobacco use were divided into two groups: marijuana users and non-marijuana users.
The researchers found that of the 28,535 cannabis users with cardiovascular risk factors involved in the study, 20 percent had an increased chance of having a major heart or brain event while hospitalized compared to non-users and 13.9 percent had a major adverse heart and brain event while hospitalized.
This study seems to be even less concerning than the first. The authors do not account for major differences between the two groups (the cannabis users were more likely to be male, Black, be diagnosed with AIDS, suffer from alcohol abuse, depression, uncomplicated hypertension and drug abuse).
And while the study found an increase in major heart or brain events among the weed users, it also found a lower rate of all-cause mortality among them, meaning the cannabis users died at a lower rate than the non-users (1.7 percent compared to 3.3 percent).
Takeaway
Despite the fanfare and negative headlines, these two studies aren’t quite as frightening as some fear mongers would have you believe. The studies don’t deliver irrefutable evidence that daily cannabis use is significantly damaging to the heart or that people with cannabis use disorder are bound to die from a heart event.
What they do suggest is that regular pot users should take special care of their hearts and pay attention to improving their overall cardiovascular health to mitigate any minor dangers the drug may pose. But in truth, that’s just good advice for everybody.