Letter by Herzig Regarding Article, “Electronic Cigarettes: A Scientific Review”
To the Editor:
I read with great interest the review on electronic cigarettes (EC) by Grana et al,1 which concludes that the pooled results of 5 population-based studies show a statistically significant negative correlation between EC use and cessation. They wrote that this contrasts with the assumption that EC functions as a better form of nicotine replacement therapy.
However, inferences against EC-induced cessation from any of those studies contain 1 of the following flaws:
Two of the studies (including Adkison et al2) verified participants’ EC status only at the end point, a third was a cross-sectional survey. These allow for a negative correlation attributable to a lower incidence of EC initiation among former smokers. Indeed, a large survey of dedicated users found that <0.5% had been former smokers before the onset of use.3
This effect is exacerbated by the exponential growth of EC use, likely clustering the points of initiation toward the end point, and thus further decreasing the proportion of nonusers likely to have quit during the duration of EC use.
The other studies verified EC status at the baseline (based on use within the preceding 30 days). However, being that study design only allowed entry for current smokers, all EC users entered with a history of resistance to treatment (ie, EC use without cessation).
In addition to these generic flaws, specific flaws relate to the group’s 2 statistically significant studies. One study is a survey of quit-line callers 7 months after enrollment. Thus, among those who initiated EC use before contacting the quit-line, soliciting the cessation service indicates EC’s failure to induce cessation.4 Likewise, subsequent to enrollment, the initiation of EC use indicates that the quit-line failed to induce cessation. As one researcher observed, “this is clearly a harder core group of smokers and it is no surprise that their cessation rates were lower.”4
The other study compared cessation-rates between ever-users and never-users. Being that only 17.3% of those who had ever tried EC are current users (and only 2.8% used them every day),5 ever-use is likely less of a causative factor then an indicative measure.
Because the interpretations of these results have serious implications for public health policy, I eagerly anticipate the authors’ response.
Zvi Herzig, MPH
Uvacharta Bachayim Institute
- © 2015 American Heart Association, Inc.
- Grana R,
- Benowitz N,
- Glantz SA
- Adkison SE,
- O’Connor RJ,
- Bansal-Travers M,
- Hyland A,
- Borland R,
- Yong HH,
- Cummings KM,
- McNeill A,
- Thrasher JF,
- Hammond D,
- Fong GT
- Siegel M