E-cigarettes contain a lower number of toxic substances than conventional cigarettes, but their long-term health effects are not yet clear, the National Academies of Sciences, Engineering, and Medicine concluded in a report published Jan. 23.
The report, commissioned by FDA at the direction of Congress, is the result of a comprehensive and systematic review of over 800 peer-reviewed studies on e-cigarettes. Although the research base is limited, given the relatively short time e-cigarettes have been used, the NASEM committee concluded that e-cigarettes—although not devoid of health risks—are likely to be far less harmful than conventional cigarettes.
E-cigarettes are a diverse group of products containing a heating element that produces an aerosol from a liquid that users inhale via a mouthpiece, and include a range of devices such as “cig-a-likes,” vape tank systems, and vape mods. In 2016, e-cigarette use by youths was substantially higher than cigarette smoking or use of any other tobacco product.
Millions of Americans use e-cigarettes, and e-cigarette use is generally greatest among young adults and decreases with age. Use varies substantially across demographic groups, including age, gender, race, and ethnicity. For example, among youth and adults, use is typically greater among males than females, according to the NASEM report.
Among youth—who use e-cigarettes at higher rates than adults do—there is substantial evidence that e-cigarette use increases the risk of transitioning to smoking conventional cigarettes. The NASEM report found that evidence suggests completely switching from combustible cigarettes to e-cigarettes reduces an individual user’s exposure to numerous toxicants and carcinogens, as well as reduces some short-term health outcomes.
E-cigarettes cannot be simply categorized as either beneficial or harmful, said David Eaton, chair of the committee that wrote the report, and dean and vice provost of the Graduate School of the University of Washington, Seattle.
“In some circumstances, such as their use by non-smoking adolescents and young adults, their adverse effects clearly warrant concern,” Eaton said in a statement. “In other cases, such as when adult smokers use them to quit smoking, they offer an opportunity to reduce smoking-related illness.”
Eaton and his colleagues found conclusive evidence that exposure to nicotine from e-cigarettes is highly variable and depends on the characteristics of the device and the e-liquid, as well as on how the device is operated. Also, there is substantial evidence that nicotine intake from e-cigarettes among experienced adult e-cigarette users can be comparable to that from conventional cigarettes.
Other findings include:
There is conclusive evidence that in addition to nicotine, most e-cigarettes contain and emit numerous potentially toxic substances.
There is substantial evidence that except for nicotine, exposure to potentially toxic substances from e-cigarettes (under typical conditions of use) is significantly lower compared with conventional cigarettes.
There is no available evidence whether or not e-cigarette use is associated with intermediate cancer endpoints in humans. According to NASEM, an intermediate cancer endpoint is a precursor to the possible development of cancer. For example, polyps are lesions that are intermediate cancer endpoints for colon cancer.
There is limited evidence from animal studies using intermediate biomarkers of cancer to support the hypothesis that long-term e-cigarette use could increase the risk of cancer.
The NASEM report also notes that the wide diversity within electronic nicotine delivery systems or e-cigarettes products poses a challenge for research on their risks and the public health impact.
This report shows what happens when a new product is introduced without meaningful government oversight. It demonstrates why the FDA should fully and aggressively implement the overdue e-cigarette regulations that took effect in August 2016.
Matthew Myers
“We appreciate the National Academies’ review of the complex public health considerations around e-cigarettes,” FDA Commissioner Scott Gottlieb said in a statement. “Their comprehensive report not only adds to our knowledge base, but also raises some important questions about the net effect of e-cigarettes.
“One finding that’s particularly troubling is that kids who experiment with e-cigarettes are more likely to try smoking. At the same time, the report finds that current smokers who completely switch to e-cigarettes may see improved short-term health outcomes.
“Ultimately, this report helps identify areas that need further study to better understand the net public health impact of e-cigarettes as we continue our work on policies to protect kids and significantly reduce tobacco-related disease and death. We need to put novel products like e-cigarettes through an appropriate series of regulatory gates to fully evaluate their risks and maximize their potential benefits.”
The NASEM report underscores the need for immediate FDA regulation of e-cigarettes, said Matthew Myers, president of Campaign for Tobacco-Free Kids.
MODELING OF E-CIGARETTE USE
Source: The National Academies of Sciences, Engineering, and Medicine
“It is deeply troubling that there are still so many unanswered questions about the impact of e-cigarettes on public health despite the fact they have been on the market for a decade and are being used by millions of kids and adults,” Myers said in a statement. “This report shows what happens when a new product is introduced without meaningful government oversight. It demonstrates why the FDA should fully and aggressively implement the overdue e-cigarette regulations that took effect in August 2016.
“The FDA should reverse a decision it made last year to delay until August 2022 a key requirement that e-cigarettes already on the market undergo scientific review by the FDA. In addition, the FDA should enforce the requirement that manufacturers who introduce new or modified products provide detailed information about these products and undergo FDA review before these products are allowed on the market.
“This report also shows why Congress must reject a proposal, contained in a House appropriations bill, to greatly weaken FDA oversight of e-cigarettes (and cigars) already on the market, including the candy-flavored products that appeal to kids.
“As today’s report demonstrates, effective FDA regulation is key to minimizing the risks and realizing any potential benefits of e-cigarettes.”
E-cigarettes are addictive products that require closer scrutiny by FDA, said Harold Wimmer, national president and CEO of the American Lung Association.
“The Academies’ thorough and comprehensive review of the science shows clear and convincing evidence that FDA must use its full oversight authority over e-cigarettes to protect the public health,” Wimmer said in a statement. “This report, which was done at the behest of Congress, must be used to put an end to the tobacco industry’s lingering rhetoric that these products are ‘safe’ and don’t need FDA oversight.
“This report underscores the grave mistake FDA made in July when it announced it would postpone by five years the legal requirement that e-cigarette manufacturers submit their products for FDA review in order to determine whether they should stay on the marketplace. E-cigarettes have become the most popular tobacco product among youth, continuing to attract and addict our kids to nicotine while exposing them to potentially dangerous toxins and carcinogens. FDA must enforce the Tobacco Control Act in order to protect the public health from e-cigarettes.”
E-cigarettes may help adult smokers move away from conventional cigarettes, but it does not achieve ending an addiction to nicotine, said American Heart Association CEO Nancy Brown.
“We hope that message is not lost on the public as it absorbs this latest analysis,” Brown said in a statement. “As the report concludes there is substantial evidence that users of e-cigarettes can become dependent on these products and that the nicotine intake is comparable to conventional cigarettes. We would add that there is substantial evidence that using e-cigarettes can lead to cardiovascular dysfunction and the National Academies highlights some of that research.
“We must do all we can to stop this disturbing trend before it turns another generation into lifelong tobacco addicts. While the body of research on e-cigarettes is growing, the association maintains that it is far from complete.
“We agree with the National Academies that the jury is still out on the benefits and harmful effects of e-cigarettes, especially in the long-term. Until we have sufficient scientific data, we must have strong FDA regulation of these products and any new versions that come on the market.
“As always, the association will remain vigilant of e-cigarettes and their public health impact and continue our fight to eradicate all tobacco use in our nation.”
