Does cannabis cause heart disease, particularly, coronary artery disease? That is, does cannabis clog your arteries and cause heart attacks? According to US researchers, the answer is yes. Although they admit their finding “highlights the need for further research.”
Heart disease is caused by plaque buildup in the walls of the arteries that supply blood to the heart. What this has to do with cannabis consumption is dubious at best.
They Said Red Meat Causes Heart Disease…. They Were Wrong
Researchers tell us red meat causes heart disease. Associating high fat intake with poor cardiovascular health is like calling water wet. According to researchers. That is why public health authorities recommend a low-fat diet. Yet, the connection between red meat and cardiovascular disease is not proven. Even the premise – that high cholesterol causes heart disease – is questioned by some researchers.
In 2016, a paper emerged that looked at the Minnesota Coronary Experiment. The experiment ran from 1968 to 1973. In a field where observational epidemiology studies dominate, this experiment was the closest to a randomized control trial as one could get. Over 9,000 hospitalized mental patients were fed two diets. One high in animal fats, the other high in fats from vegetable oils. According to the prevailing bias, the patients with the vegetable oils should be healthier. And while their cholesterol levels did decrease, there was no decrease in mortality.
In fact, the opposite happened. The vegetable oil patients were more likely to die during the study period than the animal fat eaters who had higher cholesterol. Since the findings didn’t confirm the researcher’s bias, the study wasn’t published until 1989. And when published, the abstract claimed there was no difference between the two groups.
So Does Cannabis Cause Heart Disease?
Heart disease doesn’t develop overnight. That’s why researchers look at large groups of people over long periods of time. Called observational epidemiology studies, these are correlational studies. They are not testing a specific intervention against a control group. All they do is look at data on a specific population over time.
Observational research can give us some insight into what types of connections exist between lifestyle and risks of a specific disease.
But all they can do is show correlation.
The cannabis study in question is of this nature. They surveyed 12,543 American participants. Cannabis use was self-reported. Of the 53.1 percent that used cannabis, 1.1 percent had heart disease. Researchers concluded that cannabis users have a higher risk of coronary artery disease.
The study’s conclusions, “emphasizes the potential harmful effects of cannabis use on cardiovascular health and highlights the need for further researcher as cannabis becomes more accepted at both a national and global level.”
Of course, another study in 2021 “showed no causal effects of cannabis use on the risk of several common cardiovascular diseases,” including coronary artery disease.
However, every one of these studies (and there are plenty more) emphasizes the need for further research. But will further research really help?
Cannabis Causes Heart Disease? The Confounding Factors
A confounding factor refers to the other variables that might influence the study. The cannabis study in question claims they controlled for these factors but it’s not clear in the research. For example, of the 12,543 participants surveyed, how many of them are on a standard American diet? The same one that promotes low-fat, vegetable oils? That is, the diet that actually contributes to heart disease?
Maybe, on average, cannabis smokers have poor health because they get the munchies and end up eating junk food late at night?
Sometimes there are factors the researchers haven’t even considered. Are the supposed cardiovascular problems associated with cannabis a result of inhaling smoke into the lungs? Would the same results show up on someone who only eats edibles?
The only way to truly determine a cause between two variables is to do an experimental study. Like a randomized control trial. Consider, masking as a way of reducing the spread of flu viruses. Plenty of observational studies confirms that masking works. But, there have been two randomized control trials. And both of them showed masking had little-to-no effect.
Sometimes it’s researchers looking to further their funding. Other times its media conglomerates looking to sell advertising space with bold headlines. However it happens, conflating correlations with causation is becoming routine. That is why this particular study calls for “further research.” All they have to do is claim there is a possible connection between heart disease and cannabis. But with observational research, it is literally impossible to say x causes y.
Dr. John Ioannidis, a professor at Stanford University, criticizes this kind of research. In his paper, “Why Most Published Research Findings are False,” he explains that, “research findings may often be simply accurate measures of the prevailing bias.”
How To Decipher Baloney Masquerading as Science
Does cannabis cause heart disease? Ask yourself whether this claim is coming from an experimental study or an observational one. Are there any conflicts of interest? Who paid for the study? Did a company with vested interests finance it? Do the researchers have a bias against cannabis? Do they work for the pharmaceutical industry?
What kind of cannabis is being tested? Were they high in THC and low in other cannabinoids? In this case, all cannabis use was self-reported. So we don’t even know how much cannabis was actually consumed. People can recall incorrectly or flat out lie about how much (or little) they consume. This happens more often than you’d think.
The devil is in the details. “Further research” won’t solve the fundamental problem with epidemiology observational studies. If anything, it’ll pile on the “literature” that claims cannabis causes heart disease. A claim that is not supported by science.