Another study has found that vaping doesn't prevent smokers from relapsing to cigarettes. The results seem to undermine the efficacy of e-cigarettes as smoking-cessation tools—until you take a closer look at the definition of "relapse."
“People using e-cigarettes to quit smoking found them to be less helpful than more traditional smoking cessations aids,” CNN said of a paper published in BMJ Tobacco Control on February 7. “In fact, nearly 60% of recent former smokers who were daily e-cigarette users had resumed smoking by 2019, the new study found.”
At first glance, the study seems to undermine the case for e-cigarette use (“vaping”) as a smoking cessation tool. But first glances, as we all know, rarely tell the whole story. A closer look at the paper indicates that its authors improperly assessed how smokers utilize e-cigarettes, thus generating results that don't reflect reality.
The researchers analyzed data on 3,578 previous-year smokers who had recently attempted to quit and 1,323 recent former smokers from the Population Assessment of Tobacco and Health (PATH) Study between 2017-2019. Participants self-reported their use of e-cigarettes or other products to quit cigarettes. The researchers then investigated who among the study participants had abstained from smoking or any tobacco products in 2019.
In this analysis of the most recent PATH Study data, smokers who reported using e-cigarettes to help them in their most recent cigarette quit attempt were less rather than more likely than other quit attempters to achieve either successful cigarette cessation or to become tobacco and e-cigarette free.
The problem with "relapse."
The significance of this study is limited by the same flaw we found in an earlier paper by two of the same authors: relapse to tobacco use was measured by the question “In the past 12 months, have you smoked a cigarette/(used product), even one or two puffs/times?” Using this metric, an individual who has almost entirely quit smoking, save for “even one or two puffs” of a cigarette, and someone who has gone back to smoking a pack a day would be counted as having relapsed.
This definition ignores the fact that many smokers gradually switch from combustible cigarettes to their electronic counterparts. This is known as "dual-use," and properly designed epidemiological studies (even those based on PATH data) and clinical trials try to account for this behavioral shift, correctly noting that replacing even some cigarette smoking with vaping is desirable because vaping is the far safer option.
Here's another way to look at it: if someone goes on a low-sugar diet and "relapses" by eating "even one or two bites" of a cookie, does that show the diet doesn't work? Obviously not, and the same is true with vaping as a smoking cessation tool. In any case, the difference in relapse rates between smokers who tried to quit with e-cigarettes and those who didn't use any tobacco or e-cigarette product wasn't statistically significant.
No evidence that vaping aids cessation?
Putting aside the study's self-reported data and fuzzy definition of “relapse,” does the paper actually undermine the efficacy of vaping as a quit-smoking aid, as CNN reported? No, and the researchers themselves acknowledged this:
Randomized clinical trials (RCTs) are the optimal design to assess the efficacy of e-cigarettes as smoking cessation aids. To date, a number of RCTs have addressed the role of e-cigarettes as an aid to quitting cigarettes, and a recent systematic review concluded, with moderate certainty, that e-cigarettes improve cessation by an estimated four additional successful quitters per 100 quit attempters when compared with nicotine replacement therapy (NRT).
The authors tried to minimize the results of these RTCs by arguing that they “may not translate to the effectiveness of the product in community settings,” citing this paper, which found that selection criteria can bias the results of clinical trials. For instance, enrolling smokers who are motivated to quit may suggest that a cessation aid is more effective than it really is. But I don't find this explanation compelling for two crucial reasons.
First, thousands of unpaid testimonials from ex-smokers worldwide confirm the results generated by several RTCs: vaping helped them reduce their smoking or give up cigarettes entirely. I don't think there is any better evidence that clinical trials translate to community settings than people announcing, “I stopped smoking thanks to e-cigarettes.”
Second, at least two studies have shown that vaping may encourage smoking cessation regardless of a smoker's intentions to quit. This is probably because vaping allows people to maintain the rituals they positively associate with smoking. For instance, in a small 2017 study, smokers developed a favorable perception of vaping devices “comparable with that of conventional cigarettes.” The Tobacco Control authors hinted at this possibility towards the end of their discussion section, observing that:
… When we looked ahead to 2019, recent former smokers had started using high nicotine e-cigarettes. The effectiveness of high nicotine e-cigarettes at preventing relapse will require another follow-up PATH survey.
Additional high-quality research would be very helpful, but "preventing relapse" is an all but useless outcome. Unless the researchers evaluate how e-cigarettes are used in the real world, the only thing their next paper will confirm is that asking the wrong question inevitably leads to the wrong answer.