In a press release issued last Thursday, the American Heart Association claimed that vaping causes severe strokes and poses a higher risk of severe strokes than smoking.
According to the press release: "E-cigarettes may pose the same or higher risk of stroke severity as tobacco smoke. ... Electronic cigarette (e-cigarettes) vaping may pose just as much or
even higher risk as smoking tobacco for worsening a stroke, according to
a preliminary study in mice presented at the American Heart
Association's International Stroke Conference 2017. ... From a brain health perspective, researchers said,
electronic-cigarette vaping is not safer than tobacco smoking, and may
pose a similar, if not higher risk for stroke severity."
The American Heart Association's statement was spread widely through the media. For example, here's just one headline that appeared: "E-cigs could raise the risk of suffering a stroke more than smoking."
The Rest of the Story
The American Heart Association's conclusion that vaping poses an equal or higher risk of suffering a severe stroke is based on a single mouse study. In this study, which has not been published or peer reviewed, but was presented last week at the American Stroke Association’s International Stroke Conference, the investigators found that mice exposed to e-cigarette aerosol for 10 days or 30 days had more severe strokes than those exposed to tobacco
To extrapolate from this single pre-clinical, animal study to population-based human health effects is ludicrous. There are many reasons why stroke-related findings from rodent studies do not translate well to humans. For example, as Braeuninger and Kleinschnitz point out:
"There are, of course, significant physiological, neuroanatomical and
metabolic differences between humans and small rodents, which are the
most widely used experimental animals in preclinical stroke research.
For example, small rodents usually require higher drug doses on a mg/kg
body weight basis for a similar effect than larger mammals.
Thus, effective doses derived from preclinical stroke studies in small
rodents cannot simply be transferred to the situation in humans, even if
adjusted for body weight."
There is no scientific justification for the American Heart Association spreading the conclusion that vaping causes strokes. Nor is there any scientific justification for spreading the message that vaping poses a higher risk of suffering a stroke than smoking.
This blatant disregard for the truth, which I would term "public health malpractice," is not only unscientific but it is also damaging to public health. There are literally millions of smokers who have considered, or are currently considering, the question of whether or not to switch from smoking to vaping. Thanks to the American Heart Association, we can expect that huge numbers of smokers will choose to stick with smoking and that many ex-smokers - who quit via e-cigarettes - will decide to return to smoking.
After all, if vaping poses a greater risk of stroke than smoking, then there is absolutely no reason to quit smoking using e-cigarettes. You'd be better off smoking. And if you already quit smoking by switching to e-cigarettes, then you'd be better off returning to smoking than continuing to vape. Why take a chance of increasing your risk of suffering a stroke?
You can see why I call this an example of public health malpractice. The American Heart Association is essentially advising smokers that they are better off continuing to smoke than quitting smoking and switching completely to vaping. This is perhaps the most absurd medical advice I have ever heard in my entire career in medicine and public health. Even the tobacco companies - in the worst of their behavior - never told smokers that they would be at greater risk of disease if they quit smoking. But that is precisely what the American Heart Association is essentially telling smokers.
If the American Heart Association has any regard for scientific accuracy and professional responsibility in communication, it will offer an immediate retraction, correction, and apology for this action.
If that happens, I will report it here as soon as I become aware of it.