More real world evidence that e-cigs make it harder to quit cigarettes

The evidence that e-cigarettes do not work for smoking cessation just keeps piling up.

The latest high quality real world study, “Effectiveness of e-cigarettes as aids for smoking cessation: evidence from the PATH Cohort Study, 2017-19,” published by Ruifeng Chen and colleagues at UCSD in Tobacco Control reports on the association between e-cigarette use and smoking and tobacco cessation in the real world from 2017-2019.  This is an important time period because in 2017, there was a 40% surge in e-cig sales, driven by Juul with 75% market share. Because of Juul’s introduction of nicotine salt technology, it delivers higher levels of nicotine that earlier generation e-cigarettes.  Juul and e-cigarette advocates claim that this higher nicotine delivery makes Juul more likely to help smokers quit cigarettes.

PATH is a huge longitudinal study funded by the FDA that follows people forward in time over several years and collects detailed information on tobacco product use and related behaviors.  It is widely considered the best single source for evidence on tobacco product use.

But, following 3578 smokers who were trying to quit in 2017 forward in time didn’t produce any evidence that smokers trying to quit were part of this surge.  Use of e-cigs as a cessation aid dropped by 25% and virtually no-one was using Juul.  (At the same time, Juul was taking off with kids.)

To assess e-cigarettes as a cigarette cessation aid, the authors compared 12+ month cigarette abstinence between 1) any e-cigarette for quit attempt vs anyone who didn’t use an e-cigarette; 2) any e-cigarette vs NRT or pharmaceutical aid only for quit attempt. They also compared those who used e-cigarette only vs NRT or pharmaceutical aid only in a sensitivity analysis. To assess if e-cigarettes prevent relapse to cigarettes, they estimated the risk difference in rates of relapse to cigarette smoking between any e-cigarette vs no e-cigarette in 2019. 

The results are summarized in the graph above, which is Figure 1 in their paper.

Quitting cigarettes was 7.7% lower among those who used e-cigarettes to quit than those who didn’t use e-cigarettes to quit.  E-cigarettes also performed significantly worse than FDA approved therapies (NRT or prescription cessation aids).

The results were similar for abstinence from all tobacco products.

One bit of good news in the paper is that fewer smokers are attempting to quit with e-cigarettes than FDA-approved therapies that have been shown to work or cold turkey, which also works better than e-cigarettes.

The authors sum up their findings: “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, not more, likely than other quit attempters to achieve either successful cigarette cessation or to become tobacco and e-cigarette free.Our analysis suggests that the 2017 JUUL marketing campaigns were not effective in encouraging smokers to use JUUL products to help with quit attempts, unlike their effectiveness in encouraging young people to initiate nicotine use with their products.” 

Predictably, the pro-e-cigarette Science Media Centre in the UK immediately released a statement by John Britton dismissing the UCSD study:

“The findings of this observational study of quitting and e-cigarette use in the USA are fundamentally flawed by confounding by severity, whereby the heaviest (most addicted) smokers, having tried and failed to quit using NRT or other treatments in the past, or who have declined to try to quit in the past, then try e-cigarettes.

“This is probably why they conflict with the findings of meta-analyses of the multiple, well-designed clinical trials that have demonstrated that e-cigarettes are effective quitting aids, and which led to the UK National Institute for Health and Care Excellence (NICE) recommending e-cigarettes to help smokers to quit in guidance published at the end of 2021.”

One wonders if Britton read the UCSD paper.

Most important, the UCSD researchers did control for level of nicotine addiction through several measures of tobacco use as part of their careful matching of e-cigarette users with similar smokers who did not use e-cigarettes using propensity score matching.  This process is clearly described in the main text of the paper and documented in great detail in the supplementary appendix.

Second, the UCSD researchers did recognize that the randomized controlled trials indicate that e-cigarettes, when delivered under controlled conditions as part of a supervised cessation effort, were associated with increased quitting but clearly made the point that this effect did not carry over into the real world. In fact, the real-world effect of e-cigs on quitting smoking was opposite what the RCTs showed: 

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, not more, likely than other quit attempters to achieve either successful cigarette cessation or to become tobacco and e-cigarette free. Rather than e-cigarettes adding four additional successful cigarette quitters per 100 quit attempters compared to pharmaceutical aid users as concluded by a systematic review of RCT [randomized clinical trial] data, in this study, e-cigarette use was associated with 7 fewer successful quitters per 100 quit attempters. Further, switching to e-cigarettes did not reduce the risk of relapse to cigarette smoking compared to other recent former smokers. Instead, nearly 60% of recent former smokers who were daily e-cigarette users had relapsed to cigarette smoking by 2019 ([PATH] Wave 5). [emphasis added]

This finding reinforces the fact that well-done population studies exemplified by the UCSD study are more relevant than randomized controlled trials for assessing the impact of e-cigarettes as consumer products. By relying on the RCTs authorities in UK are pushing products on the public that at best are worthless and at worst keep people smoking by displacing effective FDA-approved therapies.

These real world findings are directly relevant to FDA as it continues to work on whether or not to determine that e-cigarettes in general and Juul in particular, should be authorized for sale because doing so would be “appropriate for the protection of public health.”

  • The whole justification for authorizing e-cigarettes for sale is that they theoretically are a less dangerous replacement for cigarettes.  This study shows that adults are not using e-cigarettes to quit (what the FDA and tobacco companies call “switching completely”).
  • Moreover, e-cigarettes do not work as well for smoking and tobacco cessation in the real world as FDA-approved medications or even quitting “cold turkey” without any aids.  So, there is no public health loss for not having them available on the market.

Here is the abstract:

Objective: To assess the effectiveness of e-cigarettes in smoking cessation in the USA from 2017 to 2019, given the 2017 increase in high nicotine e-cigarette sales.  

Methods: In 2017, the PATH Cohort Study included data on 3578 previous year smokers with a recent quit attempt and 1323 recent former smokers. Respondents reported e-cigarettes or other products used to quit cigarettes and many covariates associated with e-cigarette use. Study outcomes were 12+ months of cigarette abstinence and tobacco abstinence in 2019. We report weighted unadjusted estimates and use propensity score matched analyses with 1500 bootstrap samples to estimate adjusted risk differences (aRD).  

Results: In 2017, 12.6% (95% CI 11.3% to 13.9%) of recent quit attempters used e-cigarettes to help with their quit attempt, a decline from previous years. Cigarette abstinence for e-cigarette users (9.9%, 95% CI 6.6% to 13.2%) was lower than for no product use (18.6%, 95% CI 16.0% to 21.2%), and the aRD for e-cigarettes versus pharmaceutical aids was -7.3% (95% CI -14.4 to -0.4) and for e-cigarettes versus any other method was -7.7% (95% CI -12.2 to -3.2). Only 2.2% (95% CI 0.0% to 4.4%) of recent former smokers switched to a high nicotine e-cigarette. Subjects who switched to e-cigarettes appeared to have a higher relapse rate than those who did not switch to e-cigarettes or other tobacco, although the difference was not statistically significant.  

Conclusions: Sales increases in high nicotine e-cigarettes in 2017 did not translate to more smokers using these e-cigarettes to quit smoking. On average, using e-cigarettes for cessation in 2017 did not improve successful quitting or prevent relapse.

The full citation is:  Chen R, Pierce JP, Leas EC, Benmarhnia T, Strong DR, White MM, Stone M, Trinidad DR, McMenamin SB, Messer K. Effectiveness of e-cigarettes as aids for smoking cessation: evidence from the PATH Study cohort, 2017-2019. Tob Control. 2022 Feb 7:tobaccocontrol-2021-056901. doi: 10.1136/tobaccocontrol-2021-056901. Epub ahead of print. PMID: 35131948.  It is available here.

Here is a CNN story on the paper.

Published by Stanton Glantz

Stanton Glantz is a retired Professor of Medicine who served on the University of California San Francisco faculty for 45 years. He conducts research on tobacco and cannabis control and cardiovascular disease/

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