The E-Cigarette Debate: What Counts as Evidence?

Amy Lauren Fairchild, PhD, MPH; Ronald Bayer, PhD; Ju Sung Lee, MHA


Am J Public Health. 2019;109(7):1000-1006. 

In This Article


But what of the risks the "safer" but not "safe" e-cigarettes pose to nonsmokers? The imperative to protect "innocent bystanders" became central to tobacco control policy in the United States beginning in the 1970s, even before the evidence was definitive.[20] Public health defended bans on smoking in public settings based on an obligation to create healthy environments for nonsmokers. This policy commitment continues to define US tobacco control. Three years before the NASEM report, virtually the entire US public health community urged the Department of Housing and Urban Development (HUD) to ban both combustible and e-cigarettes in all public housing based on the risk to nonsmokers. In a letter to HUD Secretary Julián Castro, nearly 40 US public health organizations argued, "E-cigarette aerosol contains nicotine, which is absorbed by users and bystanders" and "is not as safe as clean air."[21] The New York State Public Health Association strongly supported the ban, pointing to "research indicating that harmful chemicals and carcinogens are in the aerosol coming from these devices."[22] Likewise, the 2016 US surgeon general's report, "E-Cigarette Use Among Youth and Young Adults," underscored the importance of protecting the public "from both secondhand smoke and secondhand aerosol" to "prevent involuntary exposure to nicotine and other aerosolized emissions from e-cigarettes."[13] (p188)

Against this backdrop, NASEM concluded that because e-cigarettes contained and emitted potentially toxic substances, "using e-cigarettes in indoor environment may involuntarily expose non-users to nicotine and particulates, but at lower levels compared with exposure to secondhand smoke from combustible tobacco cigarettes."[11] (p622) While the NASEM report discussed the general pharmacology of nicotine, it was "not intended to be a systematic review of the topic."[11] (p96) On the heels of the NASEM report, the US Centers for Disease Control and Prevention stated in information for consumers, "e-cigarette aerosol is not harmless. It can contain harmful and potentially harmful substances, including nicotine, heavy metals like lead, volatile organic compounds, and cancer-causing agents."[12] Most notably, the potential health threat of nicotine itself, which in the past had not been the subject of systematic inquiry, has now emerged as a focus of biomedical research and policy concern.[23]

In England, by contrast, health officials pointed out that the health risks of secondhand vape lacked an evidentiary foundation. PHE underscored, "There have been no identifiable health risks of vaping to bystanders."[8] (p162) Although the report underscored that "adolescent nicotine use (separate from smoking) needs more research,"[8] (p12) the risk of nicotine exposure was of secondary importance given a longstanding understanding that "people smoke for the nicotine but die from the tars."[6] (p1431) Similar to NASEM, then, PHE also chose not to conduct a systematic review regarding nicotine. Rather, it looked to a Royal College of Physicians report, in addition to any new evidence that might suggest risk, to support the conclusion that the harms of nicotine were "very minor."[8] (p61) Ann McNeill, one of the authors on all of the PHE reports, remained unswayed about the dangers of nicotine even as Juul, which stirred apprehension in the United States based on a nicotine profile that mirrors tobacco cigarettes, was introduced into the UK market. In July 2018, Scientific American quoted McNeill, who said, "We need to de-demonize nicotine."[24]