Do electronic cigarettes help smokers give up tobacco? A growing body of research supports that conclusion, but not all experts are convinced, including the authors of a study just published by JAMA Network Open.
The researchers analyzed the outcomes of former smokers from the Population Assessment of Tobacco and Health (PATH) study. These were adults who identified as smokers at the beginning of the study who, at their first follow-up a year later, reported quitting. Use of e-cigarettes or some other “noncigarette tobacco product” was assessed at that same follow-up. Since there were four “waves” in the Path study, the researchers put participants from waves 1-3 in one cohort (7,089 individuals) and participants from waves 2-4 in a second cohort (6,515 individuals).
Results:
"In this study using a nationally representative cohort, we did not find evidence that switching to e-cigarettes prevented relapse to cigarette smoking. We identified 9.4% of adults categorized as previous-year established smokers had become recent former smokers at follow-up 1 ... Among these recent former smokers, in both unadjusted and adjusted analyses we found no evidence to support the hypothesis that switching to e-cigarettes reduced relapse to cigarette smoking, whether or not e-cigarettes were used daily."
As we'll see, the significance of these results comes down to the definition of “relapse” and “tobacco product.” Given the broad and confusing definitions employed, the study doesn't add much to our understanding of electronic cigarettes.
The dual-use problem
The authors claimed that “The potential for harm reduction with e-cigarettes requires that those attempting to quit successfully switch completely away from cigarettes and not become dual-product users.” But this is an unjustified assumption. If smokers substitute vaping for, say, two of the cigarettes they usually consume daily, they are reducing their exposure to the carcinogens in tobacco. As public health researcher Carl V. Phillips has pointed out, vaping "does not add to the risk of smoking because it almost always replaces some smoking rather than supplementing it."
This is an important point because study participants who switched to e-cigarettes were categorized as relapses at their second follow-up if they smoked just one cigarette, “even 1 or 2 puffs.” This included 33.4 percent of daily e-cigarette users and 36.3 percent of participants who reported any e-cigarette use (Table 3). Given the broad definition of “relapse,” it's not clear if these individuals became dual users or had just gone back to smoking cigarettes.
As my colleague Dr. Chuck Dinerstein pointed out, the crux of the study was that participants who used no tobacco were most likely to have quit at one year compared to participants who used any tobacco product or an e-cigarette. But look at the last column of Table 3; there was really no difference between the participants who used any tobacco product and those who didn't.
In other words, quitting is impossible—and e-cigarettes didn't seem to help smokers quit. It then comes down to this: do you want to inhale vaporized nicotine or nicotine and combustion products? The answer is obvious to most smokers who are concerned about their health.
The researchers, to their credit, acknowledged that e-cigarette users “were also more likely to requit for at least three months than those who did not use tobacco.” They called for more research to determine if this was “a pattern of chronic quitting and relapsing to cigarette smoking or whether it is part of progress toward successful quitting.”
More data are always helpful, but the pattern they described seems to fit the evidence from existing studies. The researchers pointed to recent clinical trials, for example, showing that smokers randomized to vaping and counseling were more likely to be cigarette abstinent for one year or three months, respectively, compared to smokers who used nicotine patches.
Cessation vs. relapse
The difference between those trials and the new JAMA paper is that the earlier studies “focused on e-cigarettes as cessation aids rather than on whether individuals who smoke can switch to e-cigarettes and not relapse to smoking,” the authors noted. It's true that vaping is useful because it allows many smokers to permanently quit, but cigarette abstinence for a year is an unnecessarily narrow standard of success. By that metric, someone who vapes daily but occasionally has a cigarette with a drink has relapsed, though they've effectively quit smoking.
The clinical research tends to recognize that most smokers don't immediately and entirely switch to e-cigarettes. These studies often look for one-year abstinence, but they may also count shorter smoke-free periods as secondary outcomes.
Confusing definitions
The JAMA authors acknowledged that there is disagreement among experts over whether to define e-cigarettes as tobacco products. They nonetheless classified e-cigs as tobacco in their study, pointing out that the FDA does as well. While that's correct, there is no justification for such a classification, by the FDA or anyone else. E-cigarettes often contain nicotine, but so do gums and patches, which are instead classified as smoking cessation drugs.
All things considered, this paper does more to confuse than it does to inform us about the health risks and benefits associated with vaping. Two conclusions seem relatively clear at this point: e-cigarettes are likely far safer than their combustible counterparts, and they seem to offer many smokers a pathway to cessation.
Cameron English
Director of Bioscience
Cameron English is a writer, editor and co-host of the Science Facts and Fallacies Podcast. Before joining ACSH, he was managing editor at the Genetic Literacy Project.
