A new study published online today in the journal Pediatrics purports to show that electronic cigarettes are a gateway to smoking among youth. The study followed a sample of approximately 150 never-users of e-cigarettes and 150 ever users of e-cigarettes for one year. Both groups consisted entirely of never smokers. At one-year follow-up, the initiation of smoking was compared between the two groups. E-cigarette users were found to be six times more likely to have initiated smoking. Based on these findings, the paper concludes that e-cigarette use among youth increases the risk of progression to smoking: "These findings suggest that e-cigarette use may promote smoking during the transition to adulthood ... ."
(See: Barrington-Trimis JL, et al. E-cigarettes and future cigarette use. Pediatrics 2016; 138(1): e20160379. Published online ahead of print on June 13, 2016.)
The Rest of the Story
study is virtually meaningless in terms of its evaluation of the
Baseline e-cigarette use was defined as ever
even one puff of an e-cigarette. And smoking initiation was similarly
defined as ever having taken even one puff of a cigarette. So the study
did not document that even one subject in the study was ever a regular
vaper. It is entirely possible (and in fact
likely) that the majority of these kids had experimented with
e-cigarettes, failed to become vapers, and then turned to regular
cigarettes. In fact, it’s entirely possible that had these kids been
able to stick with vaping, they would never have become smokers.
In addition, the study counted anyone who had even puffed a cigarette
as being a smoker. So theoretically, a subject could have had a single
puff of an e-cigarette and hated it, and then had a single puff of a
cigarette and hated it, and they would be considered
someone who initiated smoking because of first becoming addicted to
the study does show, quite convincingly, is that kids who have a
personality type that lends itself to experimenting with e-cigarettes
more likely to experiment with regular cigarettes. There is no surprise
here and had the researchers found anything different, one would have
to question the validity of the study findings. Frankly, the study
doesn’t really add any knowledge that we didn’t
have already. It simply confirms what we already knew: kids who are
more likely to experiment with e-cigarettes are more likely to
experiment with tobacco cigarettes.
In fact, what this study is basically documenting is that having ever
tried an e-cigarette is a better indicator of susceptibility to smoking
than the traditional measures of smoking susceptibility. That’s really
all one can conclude
from the study. The key point is that the e-cigarette group consisted
of youth who had ever puffed on an e-cigarette, not youth who reported
being regular vapers. In order for the gateway hypothesis to be true,
kids would have to become regular vapers – addicted
to nicotine – and then move on to smoking. The paper provides no
evidence that this is the case.
The rest of the story is that despite the way the results are being interpreted, the truth is that the study provides absolutely no evidence that electronic cigarettes are a gateway to smoking or that the use of vaping products increases rates of smoking initiation among youth. What the study demonstrates is merely that youth who experiment with e-cigarettes are more likely to experiment with cigarettes as well.
It is important to recognize that an equally plausible (and I think more likely) explanation of the results is that the ever e-cigarette using youth who progressed to smoking did so because they failed to take up vaping, rather than because they experimented with e-cigarettes. Had they become regular vapers, it is much less likely that they would have progressed to real smoking because after getting used to the sweet and tasty flavors of e-cigarettes, it is implausible that they would then become attracted to the harsh taste of real tobacco smoke.
Either way, the findings from this study do not provide any evidence to support the gateway hypothesis.
However, population-based data on trends in youth vaping and smoking released last week do provide evidence that relates to the gateway hypothesis. But those data suggest that e-cigarettes are a gateway away from smoking. In other words, as vaping has become more popular among youth, it has displaced cigarette smoking and contributed towards the de-normalization of cigarette smoking.
In fact, the strongest argument against the paper's interpretation of its findings is their inconsistency with the population-based data. If youth who experiment with e-cigarettes really were six times more likely to initiate smoking, then given the high level of experimentation, the observed rate of youth smoking would certainly be substantially higher than revealed by the Youth Risk Behavior Survey. Youth smoking rates would not have experienced a 41% decline concomitant with a 24-times increase in e-cigarette experimentation if e-cigarette use were really a substantial promoter of smoking initiation.