New Study Claims E-cigs Don’t Help With Long-Term Quitting
New Study Claims E-Cigs Don’t Help Smoker Quit in the Long-Term
One of the most important and hotly-contested points about e-cigarettes is whether they help smokers kick their combusted tobacco habit, and a new study claims that there is very little evidence for their long-term effectiveness. The finding is based on previously conducted studies, however, and conflicts with a recent Cochrane review of the evidence, suggesting that there is more to this story than meets the eye. So, is the evidence for e-cigs’ long-term effectiveness really lacking, or has this study overlooking something crucial?
The Study – Looking at the Long-Term Evidence on E-Cigs for Quitting
The study was presented at a conference, and is therefore only available as an abstract – with no full, peer-reviewed version. This isn’t a huge problem, but it means that information about what the authors actually did is very limited. The abstract explains that the authors read 297 full texts about e-cigarettes (available as of May 2014), in the end settling on just four studies that met the inclusion criteria.
Two of these studies were randomized controlled trials and two were uncontrolled, before-and-after studies, but unfortunately the abstract offers no information as to which studies were actually included. From the information provided, it’s clear that one of these was the randomized controlled trial comparing e-cigs to patches for quitting smoking. Needless to say, there have been many studies published since May 2014, so this is only a review of a small portion of the evidence to date.
The Findings: Do E-Cigarettes Help Smokers Quit?
The researchers pooled the results of the four quitting studies to produce an estimate of the effectiveness of e-cigs for quitting smoking, finding that smokers using e-cigarettes were 71 percent more likely to have quit smoking after one month than those using a placebo, but at three months and six months, these differences disappeared. However, a closer look at the statistics underlines the uncertainty in this conclusion.
Since you can’t possibly test every smoker in the world to see what the true average chance of quitting using e-cigarettes is, every study conducted ultimately does its best to estimate how likely it is. To account for the uncertainty in an estimate based on a small number of data points, researchers use “confidence intervals,” which ordinarily say, “based on this estimate, we can estimate with 95 percent confidence that the actual answer will be between this number and this number.”
In the one-month results in this study, the best estimate for the odds of quitting with e-cigarettes was 1.71 (71 percent more than the comparative value of 1 for the placebo), with 1.08 and 2.72 as the probable lower and upper limits for the true value. Since the lower limit was above 1.00, the researchers were able to say there was a significant difference between vapers and placebo users. At three months, the best estimate for the odds was 1.95 (95 percent more than the placebo), but the confidence interval was between 0.74 and 5.13. Since the lower bound (0.74) was less than one, this is non-significant, but the true result could be anywhere from this to over five times the odds of quitting with a placebo. For six months, the best estimate was a 32 percent increase in odds, but the confidence interval ranged from 0.59 to 2.93, again non-significant because the interval includes the no-difference mark of 1.
One thing that’s immediately obvious from this is that there’s a lot of uncertainty in these estimates, and the finding is still consistent with the idea that e-cigs do help with long-term quitting. Clearly (as the authors point out), as of May 2014, more evidence was needed to make any sort of definitive determination about e-cigs’ effectiveness as long-term quitting aids.
The Cochrane review mentioned above included studies up to July 2014, and despite only having an extra couple of months, found the same two randomized controlled trials and 11 uncontrolled, before-and-after studies. The analysis based on the trials showed that nicotine e-cig users were 2.29 times more likely (confidence interval: 1.05 to 4.96) to quit over 6 to 12 months than those using placebo e-cigs, and were 31 percent more likely (confidence interval: 1.02 to 1.68) to reduce their smoking by 50 percent or more. Although – like this study – their analysis of the one randomized controlled trial comparing e-cigs to patches found no difference in quit rates, they also looked at reductions in smoking, finding that vapers were 41 percent more likely to reduce smoking than patch users.
Many other studies were also conducted after both of these reviews. For example, one real-world study published in August 2014 found that quitters who chose to use e-cigarettes were 61 percent more likely to quit than those choosing nicotine replacement therapy. Other real-world studies have also shown positive effects and small clinical trials have also suggested that e-cigarettes do help with long-term quitting.
As well as the limitations imposed by the small number of included studies in this recent review, studies done prior to May 2014 were also only of “cigalike,” first-generation devices, which don’t provide nicotine as efficiently as later-gen options, and appear less effective for helping smokers quit.
Conclusion: Outdated Data on Outdated E-Cigs, and Not Much of It
Clearly, in the rapidly-evolving world of the e-cigarette, this handful of studies provides outdated evidence (released over a year ago and using inferior products) which is of limited validity considering things learned since then. The wide confidence intervals will be narrowed by more research, and studies conducted since then (and a more reliable systematic review conducted only months later) do offer evidence of e-cigs’ long-term effectiveness for quitting smoking.
However, there is a grain of truth to the claims being made. We – and many, many other people around the world – have quit smoking through vaping, but there genuinely is only limited scientific evidence for their effectiveness, and more studies really are needed to see how big an effect – assuming one does genuinely exist – e-cigs have on smoking habits. Currently, many positive studies have small numbers of participants – a fact which led the Cochrane reviewers to grade the evidence as “low” or “very low” quality – and we will only be able to definitively answer the question when we have larger studies on more modern e-cigarettes.
The only truly important thing, though, is whether it works for you. A randomized controlled trial can’t really tell you what will happen to you personally; you can only really give it a try and see if it works.
- Huffington Post: New Study Casts Doubt On E-Cigarettes’ Long-Term Ability To Break Smoking Addiction
- Electronic cigarettes for smoking cessation and reduction (2014) McRobbie, H. al.
- EurekAlert!: Evidence that electronic cigarettes are effective for smoking cessation long-term is lacking
- Electronic cigarettes for smoking cessation: a randomised controlled trial (2013) Bullen, C. et. al.
- Real-world effectiveness of e-cigarettes when used to aid smoking cessation: a cross-sectional population study (2014) Brown, J., al.
- A longitudinal study of electronic cigarette use in a population-based sample of adult smokers: Association with smoking cessation and motivation to quit (2014) Biener, L. and Hargraves, J. L.
- Effectiveness of the electronic cigarette: An eight-week Flemish study with six-month follow-up on smoking reduction, craving and experienced benefits and complaints (2014) Adriaens, K. al.
- Success rates with nicotine personal vaporizers: a prospective 6-month pilot study of smokers not intending to quit (2014) Polosa, R. al.
- Nicotine absorption from electronic cigarette use: comparison between first and new-generation devices (2014) Farsalinos, K., al.