A congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine has found that electronic cigarettes (e-cigarettes) are likely to be far less harmful than conventional cigarettes, although they are not without health risks.

The committee that conducted the study, led by David L. Eaton, PhD, dean and vice provost of the Graduate School of the University of Washington, Seattle, identified and examined more than 800 peer-reviewed scientific studies and found that e-cigarettes contain fewer numbers and lower levels of toxic substances than conventional cigarettes, and using e-cigarettes may help adults who smoke conventional cigarettes quit smoking. Long-term health effects, however, are not yet clear. Young adults have been found to use e-cigarettes at higher rates than adults and have an increased risk of transitioning to smoking regular cigarettes from e-cigarettes.

“E-cigarettes cannot be simply categorized as either beneficial or harmful,” said Dr Eaton. “In some circumstances, such as their use by non-smoking adolescents and young adults, their adverse effects clearly warrant concern. In other cases, such as when adult smokers use them to quit smoking, they offer an opportunity to reduce smoking-related illness.”

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The study found that e-cigarette aerosol contains fewer numbers and lower levels of toxicants than smoke from combustible tobacco cigarettes. Nicotine exposure can mimic that found with use of combustible tobacco cigarettes, but it is highly variable. The exposure to nicotine and toxicants from the aerosolization of flavorings and humectants depends on device characteristics and how the device is used.

The committee evaluated the current state of knowledge on outcomes, including dependence and abuse liability, cardiovascular diseases, cancers, respiratory diseases, oral diseases, reproductive and developmental effects, and injuries and poisonings. Overall, the evidence reviewed suggests that e-cigarettes are not without biologic effects in humans. For instance, use of e-cigarettes results in dependence on the devices, though with apparently less risk and severity than that of combustible tobacco cigarettes. Yet the implications for long-term effects on morbidity and mortality are not yet clear.

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For youth and young adults, there is substantial evidence that e-cigarette use increases the risk of ever using combustible tobacco cigarettes. This evidence also suggests that they might also increase adult cessation of combustible tobacco cigarettes.

Although e-cigarettes are not without risk, compared with combustible tobacco cigarettes, they contain fewer toxicants, can deliver nicotine in a similar manner, and might be useful as a cessation aid in smokers who use e-cigarettes exclusively. However, young people who begin with e-cigarettes are more likely to transition to combustible cigarette use and become smokers who are at risk for the known health burdens of combustible tobacco cigarettes.


  1. New report: one of the most comprehensive studies on health effects of e-cigarettes; Finds that using e-cigarettes may lead youth to start smoking, adults to stop smoking [news release]. The National Academies of Sciences, Engineering, and Medicine. 23 January 2018. Accessible at: http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=24952&_ga=2.46295267.554135714.1516820655-905784784.1516820655
  2. Public health consequences of e-cigarettes. The National Academies of Sciences, Engineering, and Medicine. January 2018. Accessible at: https://www.nap.edu/resource/24952/012318ecigaretteHighlights.pdf