E-Cigarettes: Plausible Heart Risks Flagged in New Review
Definitive evidence is lacking regarding potential CV effects, but preliminary evidence suggests some reason for concern.
DUBAI, United Arab Emirates—E-cigarettes are being marketed as safer alternatives to traditional cigarettes and as aids to help people quit smoking, but there is some evidence that they could be having adverse effects on the cardiovascular system, a new review shows.
Adverse changes involving endothelial function, vascular stiffness, vasoconstriction, heart rate, blood pressure, inflammation, oxidative stress, and platelet function were observed in more than a dozen studies conducted in high-income countries, Gaurang Nazar, MBBS, PhD, and Monika Arora, PhD (Public Health Foundation of India, New Delhi), reported in a poster at the 2018 World Congress of Cardiology & Cardiovascular Health here.
Observational studies evaluating risks of CVD were limited to one US study, which demonstrated an increase in the likelihood of acute MI among people who used e-cigarettes every day (OR 1.79; 95% CI 1.20-2.66).
“Biological plausibility and possible mechanisms for cardiovascular effects of e-cigarettes have been reported in previous studies conducted in high-income countries,” Nazar and Arora wrote. “There is a need for low- and middle-income countries to conduct research on the cardiovascular effects of e-cigarettes as these are emerging markets for e-cigarettes.”
Moreover, they said, all countries, regardless of income level, “need to conduct longitudinal/cohort/case-control studies which would assess causal associations between e-cigarette use and cardiovascular diseases.”
Though e-cigarettes are widely believed to be safe, they have not been studied enough to be sure, commented Martha Gulati, MD (Banner – University Medicine Heart Institute, Phoenix, AZ).
“I’m not a big advocate of them for the reason that there’s still a lot of unknown risks related to e-cigarettes, both cardiovascular as well as cancer,” she told TCTMD. “And I think that we don’t have enough data saying that e-cigarettes necessarily even help people quit smoking.”
That said, they could be considered a tool to help people quit smoking, according to Gulati, who noted that the American College of Cardiology discussed e-cigarettes in a new expert consensus decision pathway on tobacco cessation released just last week.
“E-cigarettes have the potential for large public health benefit if they help smokers to quit smoking combustible cigarettes, especially smokers who have not been willing or able to quit using current treatments,” the authors of that document, led by Rajat S. Barua, MD (University of Kansas Medical Center, Kansas City), write. “This potential benefit must be balanced against e-cigarettes’ own long-term health risks, which are largely unknown at this time, and against the potential for e-cigarettes to attract youth and young adults who might not otherwise smoke to take up their use and perhaps increase the uptake of cigarettes.”
In the absence of definitive evidence, Gulati said she worries about the long-term consequences of using e-cigarettes, particularly because they’re still delivering nicotine.
“I think that we should just reserve caution with e-cigarettes,” she said. “There’s a lot of people out there thinking that they’re safe and I think there’s chemicals in there that I’d want to know about if I’m putting them into my body. . . . If you’re going to be addicted to that for life, is it better than cigarettes? Is it still harmful? We should still be informing people.”
To get a sense of what is currently known about potential cardiovascular risks, Nazar and Arora reviewed the literature, identifying 14 studies after excluding animal, genetic, pharmacological, economic, and case studies. Those studies, all from high-income countries, suggested some possible cardiovascular harm.
The fact that e-cigarettes and other electronic nicotine delivery systems (ENDS) are freely available in most countries around the world is of concern, Nazar, Arora, and Amit Yadav, PhD (National Institute for Cancer Prevention and Research, Noida, India), noted in a second poster in which they examined how ENDS are regulated among the 195 countries that are members of the World Health Organization (WHO).
People should know what they’re putting into their bodies, and part of our job as physicians and as regulators is to help make those decisions, or at least help them be informed decisions. Martha Gulati
Overall, at least 30 countries have banned the manufacture, import, distribution, and sale of ENDS, Nazar and colleagues found. Of the remaining 165 countries, 65 have some type of regulations on the books—handling the devices as consumer or therapeutic devices, as tobacco products, or a combination of those approaches—and 100 have no regulations at all.
For Nazar et al, the message is simple: “ENDS must be regulated consistent with WHO’s position statement—prohibit production, supply, and distribution of ENDS until its design features, quality control, labelling, disposal, access to the minor and vulnerable population, safety issues, and above all its effectiveness as a cessation aid is clinically established.
“There is insufficient evidence [on which] to base policy decisions on safety and efficacy of ENDS products,” they continued. “As a precautionary principle, therefore, ENDS should be banned from the market (both retail and online sale) [until] its safety is firmly established.”
Gulati endorsed that approach.
“Certainly, if e-cigarettes panned out to be a safer substance, then I would say it’s better to go from cigarettes down to e-cigarettes . . . but I don’t think we have that comparison data yet, especially for long-term use,” she said.
Thus, calling for a ban while allowing research to continue into whether e-cigarettes are safe is “a good perspective,” Gulati said. She said lessons should be learned from the experience with cigarettes, which were readily available—and even endorsed by doctors at one time—before the safety risks were fully known.
“I just feel like introducing something else that might be unsafe is a really dangerous road to take for everyone and I would want the data,” Gulati said, who noted that there will be new US prevention guidelines coming out in the next few months that will make a statement on e-cigarettes.
“People should know what they’re putting into their bodies, and part of our job as physicians and as regulators is to help make those decisions, or at least help them be informed decisions,” Gulati said. “It’s the information that’s lacking.”
Nazar GP, Arora M. Cardiovascular health impact of e-cigarettes: research priorities. Presented at: World Congress of Cardiology & Cardiovascular Health 2018. December 5, 2018. Dubai, United Arab Emirates.
Barua RS, Rigotti NA, Benowitz NL, et al. 2018 ACC expert consensus decision pathway on tobacco cessation treatment. J Am Coll Cardiol. 2018;Epub ahead of print.
Nazar GP, Yadav A, Arora M. The regulatory conundrum of ENDS: a challenge to tobacco control efforts globally. Presented at: World Congress of Cardiology & Cardiovascular Health 2018. December 5, 2018. Dubai, United Arab Emirates.
- Nazar reports no relevant conflicts of interest.