According to the headline of a UPI news story from last week, vaping has been linked to an increased risk of having a heart attack. This research finding was reported worldwide, including a scary headline in London's Sunday Express reading: "New research claims vaping raises risk of deadly heart attacks and strokes."
This finding is profoundly important because if e-cigarette use does indeed increase heart attack risk, then the role of vaping in harm reduction comes into serious question.
The news headline stems from a paper that is being presented this week at the American Stroke Association’s International Stroke Conference in Hawaii.
According to the news coverage, the researchers used cross-sectional data from the 2016 Behavioral Risk Factor Surveillance Survey (BRFSS) and found that ever use of e-cigarettes increased the risk of reporting ever having had a heart attack, while controlling for age, gender, body mass index, history of diabetes, and smoking status. The same was true for the risk of reporting ever had a stroke.
While the abstract itself does not appear to be publicly available, the news articles report that the study found a 59% increase in heart attack risk associated with the use of e-cigarettes. According to one article: "The American Heart Association has subsequently cautioned the public against using e-cigarettes."
The Rest of the Story
It is irresponsible to use the results of this cross-sectional study to conclude (or even suggest) that e-cigarette use increases heart attack or stroke risk. Why? Because the study only assessed the relationship between "ever" having used e-cigarettes and "ever" having had a heart attack. The study has no information on which came first. In other words, it is entirely possible (and in fact quite likely) that the majority of respondents who reported having used e-cigarettes and having had a heart attack actually suffered the heart attack first and then subsequently started using electronic cigarettes because they were desperate to quit smoking after experiencing this life-threatening event.
A similar study (this one using cross-sectional data from the National Health Interview Survey) was published in the American Journal of Preventive Medicine last year and is subject to the same fatal flaw: it is highly likely that people who experienced a heart attack began using e-cigarettes in an attempt to quit smoking.
Trying to Quit Smoking Increases Your Risk of Having a Heart Attack
Using the same methodology as these studies, I examined the relationship between trying to quit smoking and heart attack risk. I used the 2016 BRFSS and modeled the risk of having had a heart attack as a function of having tried to quit smoking (and succeeding for at least one day). I controlled for age, gender, body mass index, diabetes, and smoking status.
Making a serious quit attempt is associated with a significant increase in heart attack risk. It actually increases your heart attack risk by 41%.
Obviously, what is going on here is not that quitting smoking increases your risk of having a heart attack. Instead, what is happening is that smokers who experience a heart attack are more likely to try to quit smoking.
But the same reasoning used by researchers to conclude that vaping increases heart attack risk supports the conclusion that trying to quit smoking increases heart attack risk.
For that matter, one could show that use of asthma inhalers is associated with an increased risk of having asthma, that use of insulin is associated with an increased risk of diabetes, or that the consumption of gluten-free food increases your risk for Celiac disease (caused by gluten allergy).
For those who are curious, trying to quit smoking is associated with a 38% increase in the risk of stroke.
Clearly, physicians should warn their smoking patients not to try to quit, as quitting appears to be associated with an increased risk of heart disease and stroke.
Sadly, we don't have to recommend that physicians counsel smokers not to try to quit -- the American Lung Association is already doing that.