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


The 2 reports' analyses of the threat to children represented yet another yawning gulf about what the evidence revealed. NASEM concluded, "There is substantial evidence that e-cigarette use increases risk of ever using combustible tobacco cigarettes among youth and young adults."[11] (p10) The committee identified 9 studies that met the evidentiary bar.[11] For the analysis of the relationship between e-cigarette use and smoking over the past 30 days, only 2 studies qualified.[11] While the report did note contradictory data, it determined that observational or ecological evidence could not provide a conclusive refutation of the risk to children. Only randomized controlled trials could meet that bar.[11] Conclusive proof, for NASEM, was the standard when it came to vulnerable populations like children.

Most important was how the head of FDA's Tobacco Division, Mitch Zeller, read the evidence in light of the NASEM Report: "For kids who initiate on e-cigarettes, there is a great chance of intensive use of cigarettes. As the regulator, we've got to factor that in."[15] How that evidence should be factored in was clear to Shannon Lea Watkins, a member of Stanton Glantz's research team, which had long warned of threats posed by e-cigarettes. "It comes down to this tradeoff between definitely hurting kids and maybe helping some adults," she said. "To me the tradeoff sounds quite clear."[25] An analysis conducted by Kozlowski and Warner threw into high relief how differently the tradeoff could be perceived.[26] Citing evidence from large, cross-national studies, they argued that adoption of e-cigarettes as a smoking harm-reduction tactic "might come at the cost of additional new smokers among the younger generation. While unpleasant to contemplate, this cost must be compared to the far more immediate benefit in terms of health consequences that would be realized by adults quitting smoking."[26] (p213)

For the PHE, the evidence could not be read as providing proof that e-cigarettes were serving as a gateway to tobacco for young people. "Despite some experimentation with these devices among never smokers, e-cigarettes are attracting very few young people who have never smoked into regular use."[8] (p75) Linda Bauld, one of the report's authors, was unambiguous in calling the impact on youth "negligible."[14] Indeed, studies suggest that England's focus on smokers will have an impact on youth uptake: adult smoking represents a risk factor for youth uptake.[27,28]