New Study Suggests E-Cigs Are 60% More Effective Than NRT
By Lindsay Fox Posted June 4, 2014
One of the most insidious ideas spread about e-cigarettes is that they will actually reduce the numbers of smokers able to quit by reinforcing nicotine addiction, or even that they’re simply ineffective for quitting. For anybody trying to peddle either of these highly unlikely arguments, a new piece of research (which is free to read) investigating the real-world use of e-cigarettes in the UK is probably not going to be an enjoyable read. The study looks at the numbers of smokers able to quit smoking through vaping in comparison to those who used nicotine replacement therapy (NRT) or tried to quit unassisted (“cold turkey”).
The findings suggest that – contrary to ill-informed, unsupported statements – smokers who choose to quit by vaping are successful more often than self-selected cold turkey or NRT users, when no further support is provided. There are some important limitations in how the research should be interpreted, however, so it’s wise to find out more about the study before declaring e-cigs to be 60 percent more effective than NRT.
- Researchers used population-based, cross-sectional surveys of English households to assess the quit-rates of smokers choosing to use e-cigs in comparison to those quitting cold turkey or with NRT, in all cases without additional behavioral support. The quit attempt had to have been made in the previous year.
- The data was taken from the Smoking Toolkit Study from 2009 (when e-cigs were first included) to 2014. The researchers controlled for potential variables such as differing levels of nicotine dependence in order to interpret the results.
- 20 percent of e-cig users, 10.1 percent of NRT users and 15.4 percent of unaided quitters were (self-reportedly) abstinent from smoking at the time of the survey.
- The fully adjusted model suggests that those choosing to quit smoking using e-cigs were 1.63 times more likely to quit than NRT users and 1.61 times more likely than cold-turkey quitters. In all four models, e-cig users were more likely to quit than those using NRT or the cold-turkey approach.
- Additional analyses conducted, excluding those who smoked less than one cigarette per day or excluding data from 2011 and earlier (when e-cigs weren’t as popular), for example, produced no change in findings the vast majority of the time.
- The study can’t be interpreted as meaning “e-cigs are 60 percent more effect than NRT” because it was a self-selected sample. Although clinical trials may enable such a statement to be made, it would only be relevant if all smokers in the world were to be given the same intervention for quitting, which they obviously aren’t.
- The research shows that e-cigarettes really do help smokers who choose to use them stop smoking, even in the absence of additional support.
What They Did – Looking at Real-World Effectiveness of E-Cigs
Many previous population-based studies have claimed to show that e-cigarettes are not effective for quitting (summarized in Stanton Glantz and associates’ recent one-sided “systematic” review of the evidence), but in most cases it wasn’t even determined whether or not those classed as e-cig users were actually trying to quit. It’s clear that in order to see if they’re effective for quitting in real-world situations the focus should be on those actually trying to quit, and the new study aims to do just that, comparing e-cigarettes to NRT and cold-turkey quitting among a population-based sample.
In clinical studies and many other pieces of research, NRT (and other interventions for quitting smoking) is offered with behavioral support, but this doesn’t reflect real-world usage. Most people just buy the patches or gums and try to quit, rather than also heading out to a counselor for additional support. The new study therefore focuses on unaided attempts, including any participants who’d made a serious quit attempt (“serious” meaning the intention “I will not smoke a cigarette again”) in the previous year (prior to the survey) using e-cigarettes, NRT or the cold turkey method, without medication or counseling (or combinations of NRT and e-cigs).
The data was taken from the Smoking Toolkit Study, a nationally-representative monthly survey of households in England. This study uses data from when e-cigarettes were first included in the survey questions (in July 2009) up until February 2014, and looked at the self-reported abstinence from smoking among participants using different approaches. In addition, the researchers had data to allow them to control statistically for important variables such as their level of nicotine dependence and several others. They constructed four models, one of which assessed the basic effect (accounting for only quitting method), one assessing all relevant variables and their interactions with one another, and two with levels of control over variables between these two extremes.
What They Found – E-Cigarette Users are More Likely to Have Quit
In total, 5,863 smokers were included in the study, with 59.3 percent trying to quit cold turkey, 32.8 percent with NRT and just 7.9 percent (464 users) attempting to quit by vaping. There were several differences in demographics between the smokers choosing specific approaches, but the most important factor is that those using NRT scored higher on tests of cigarette dependence than either of the other groups and smoked more cigarettes. Vapers smoked more and were more dependent than those trying to quit unassisted, and unassisted quitters were also more likely to have only smoked less than one cigarette per day.
Overall, 20 percent of e-cigarette users reported having successfully quit, compared to 10.1 percent of NRT users and 15.4 percent of those quitting cold turkey. In the model that didn’t take account for important variables, e-cigarettes users were 2.23 times more likely to have quit than over the counter NRT users and 1.38 times more likely to quit than those trying cold turkey. In the fully-adjusted model, e-cig users were 1.63 times more likely to quit than NRT users and 1.61 times more likely to quit than unassisted smokers.
Further analyses were conducted on the data, but these generally had little effect on the comparative quit-rates between approaches. For example, when participants who smoked less than one cigarette per day were excluded, e-cig users were 1.59 times more likely to be non-smokers by the time of the survey than NRT users and 1.63 times more likely to have quit than those stopping cold turkey. The greater effect in comparison to cold turkey quitters seen in this analysis is due to the much larger proportion of cold turkey quitters who smoked less than one cigarette per day (2.8 percent of them, compared to 0.7 percent of the vapers and 0.8 percent of the NRT users), for whom it is obviously easier to quit.
Between 2009 and 2011, not many people used e-cigarettes, and when this data was discounted, analyses revealed little difference (vapers 1.59 times more likely to quit than NRT users and 1.46 times more likely than those using no aid). The final analysis looked at the difference in results if only those who tried to quit in the previous six months were included or only those who started their attempt over six months ago. Using the model with the most control over variables, e-cig use was only associated with significantly greater odds of quitting when the participants making an attempt less than six months prior to the survey were used, with no significant difference for the participants who tried to quit over six months prior to the survey.
E-Cigs Are Effective for Real-World Quitting
The overall findings show that those who used an e-cig in their most recent quit attempt were more likely to report non-smoking at the time of the survey than the other two groups, with the effect persisting after controlling for age, gender, social “grade,” nicotine dependence, time since the quit attempt and other factors such as prior attempts in the past year and the year the survey was taken. In other words, the results show that, adjusted or not, those who choose to use e-cigarettes were more likely to have quit smoking than unassisted quitters or those using over-the-counter NRT.
It may be tempting to interpret this finding as suggesting that e-cigarettes are 60 percent more effective than NRT for quitting smoking, but this isn’t a valid interpretation of the study, as Carl V. Phillips argues. The basic reason for this is that the sample was self-selected. The participants weren’t randomly assigned to e-cigarettes, they chose them if they wanted to use them, meaning that they’d likely tried them before or at least found them appealing. Phillips points to the cold turkey quitters as a clear explanation for this: when randomly assigned to cold turkey quitting, the rate is dismally low, at around 3 to 5 percent. However, the rates increase dramatically (as they did in this study – 15.4 percent of the cold turkey group quit) when smokers choose to quit cold turkey. This is because they want to quit smoking so much that they don’t feel like they need additional support; they’re more successful because they’re more determined. Similarly, Phillips suggests that NRT users are swayed by marketing messages and may end up believing they’ll magically lose their desire to smoke if they use patches, when in fact that isn’t the case, and consequently low quit rates are very common.
So does this mean that only a randomized controlled trial can determine if e-cigarettes are more effective than NRT across the whole population? Yes, but Phillips and the study authors point out that population-based studies are more immediately relevant than clinical trials. This is because in no real-world situation are all smokers assigned one specific cessation tool: obviously you choose what to do in the real world, so it’s somewhat irrelevant which method is more effective over the whole population. In a sense, this means that studies looking at the outcomes of smokers’ choices of quitting method are more applicable to everyday use than ones in which participants are forced into a specific group.
Of course, there are still reasons that clinical trials are valuable: the authors list many variables, including motivation to quit and mental health status, which were not controlled for in the study but could have influenced the results. However, the research did control for many variables, and it’s safe to say that the study provides evidence that e-cigarette use is leading to successful quitting of smoking in the real world. Additionally, clinical trial findings on their effectiveness are also positive, so any suggestion that e-cigs don’t help people quit is highly dubious and would need to be supported with robust evidence to be at all convincing.
There were a couple of other minor limitations noted by the authors, including the fact that abstinence was self-reported, and only referred to abstinence at the time of the survey. Although falsely claiming you’ve quit is less common in this type of research than clinical trials, it could still be a minor issue, and any relapses between quitting and the survey time wouldn’t be identified in this study if the individual had stopped smoking again before the survey.
Another potential issue is the reliance on recall, meaning that some mistakes could have been made. Specifically, the authors point out that quit attempts with an intervention (like e-cigs or NRT) would be more memorable than cold turkey attempts, so the older data may be swayed a little against e-cigarettes. The sub-group analysis for those who’d tried to quit over six months before the study seemed to indicate that e-cigs were less effective over the long term than the short term, but this may be due to this bias rather than e-cigs actually being less effective in the long-term. The recall bias explanation is supported by the finding that the non-smoking rate for cold turkey quitters making an attempt over six months before the survey was higher than those making it within the last six months: they may have simply forgotten about older, failed attempts and skewed the findings.
Conclusion: Self-Chosen Vapers are More Likely to Quit Smoking Unassisted than NRT Users
Overall, there are limitations to the findings, but they don’t really detract from the overall message that e-cigarette really do appear to be effective for quitting in the real world (i.e. where we can choose how we quit). Since smokers often quit without behavioral support, e-cigs clearly hold huge potential for saving lives and improving public health for the smokers who vaping does appeal to. As more evidence amasses in the future, we’ll undoubtedly be able to assert with confidence that e-cigs are much more effective than NRT, but for now, research indicating that they help interested smokers quit in the real-world is excellent news in itself.