On April 18, 2024 the UK Royal College of Physicians published E-cigarettes and Harm Reduction: An Evidence Review, the latest in a series of reports it has published since 2007 endorsing e-cigarettes for harm reduction. In this report, the RCP recommends that “e-cigarettes should be promoted as an effective means of helping people who smoke to quit smoking tobacco [page 43].”
As with the RCP’s conclusions about health risks and nicotine, this recommendation is based on a small fraction of the available evidence, while ignoring the much larger body of relevant work showing that that e-cigarettes as consumer products are not associated with stopping cigarettes.
The RCP relies solely on randomized controlled trials of e-cigarettes as smoking cessation interventions
Randomized controlled trials, in which participants are randomly assigned to receive a medicine or other intervention, then followed forward in time to see whether they are cured is the gold standard for evaluating medicines and other supervised clinical interventions.
A well-done RCT applies a precisely defined intervention to a precisely defined group of people to evaluate that intervention. This precision and the fact that the treatment is assigned at random means that a well-designed and well-executed RCT provides strong evidence regarding the efficacy of the therapy under consideration.
As the RCP report correctly notes:
The 2024 update of the Cochrane review of e-cigarettes
for smoking cessation found high-certainty evidence from seven randomised controlled trials (n=2,544 participants) that e-cigarettes with nicotine can help more people quit smoking than traditional nicotine replacement therapies (NRT) (risk ratio (RR) 1.59, 95% confidence interval (CI) 1.29, 1.93). [page 44]
The problem is that RCTs only directly apply to the highly controlled environment of a medical intervention and e-cigarettes are consumer products that any adult can buy and use however they want not medicines that are administered selectively.
As the RCP recognizes:
While randomised controlled trial evidence is the gold standard, its ‘real-world’ generalisability is limited, but can be augmented through observational studies in the general population. Observational studies are particularly relevant for e-cigarettes due to the rapid change in device types, patterns of uptake and usage, evolution of e-cigarette promotion and regulation, and public perceptions … [Page 55, emphasis added, citations dropped]
Fortunately, there are even more observational studies of the association between e-cigarette use in the real world than RCTs. As with the evidence linking e-cigarettes and disease, however, the RCP ignores this large body of highly relevant evidence on the actual effects of e-cigarettes on stopping smoking in the real world.
The population observational studies do not show increased stopping smoking associated with real world e-cigarette use
There have been at least two meta-analyses of the association between e-cigarette use and stopping smoking in the population (one by us [Wang et al] and one by Hedman et al). While they use slightly different selection criteria for the studies to include, both find no association between use of e-cigarettes as consumer products in the general population and stopping smoking.
Here are the results from Wang, showing both the individual study results and the pooled overall results:
Here are the results from Hedman, which limited its sample to longitudinal studies:
In addition, two long-term (3 year) longitudinal studies (Osibigun et al [2022] and Chen et al [2023]) published after these two meta-analyses were completed found that, in the long run, smokers who used e-cigarettes were less likely to stop smoking than smokers who did not use e-cigarettes.
The RCP did not present any of this information. In fact, a complete assessment of all the evidence reveals that, in the real world, e-cigarettes are not associated with stopping smoking cigarettes and, in the long run, may keep people smoking.
While RCP ignored the Wang meta-analysis when assessing the association between real-world e-cigarette use and stopping smoking, it cited it later in the report to support RCP’s recommendation that people use e-cigarettes daily
While RCP ignored the results of the Wang meta-analysis in Chapter 4 of its report (“Effectiveness of e-cigarettes for smoking cessation”), it cited it in Chapter 7 (“Encouraging uptake of e-cigarettes for smoking cessation”) to support the statement that “daily use of e-cigarettes, compared to non-use, is positively associated with smoking cessation whereas non-daily use is negatively associated” [reference 208 on page 158]. In other words, daily e-cigarette users are more likely to have stopped smoking whereas non-daily e-cigarette users are less likely to have stopped smoking. There is no overall association between using e-cigarettes and stopping smoking because in the real world people use e-cigarettes both ways.
The RCP, however, ignores the second half of the evidence in its “Key Points” at the beginning of Chapter 7 when it says, “Smoking cessation is more likely if vapes are used daily and frequently [page 141].” It then goes on to recommend “Smokers who are trying to quit using e-cigarettes should be encouraged and supported to adopt patterns of e-cigarette use most likely to lead to successful smoking cessation [page 142].” In other words, RCP is urging heavier use of e-cigarettes despite the health risks.
Why was RCP willing to use the population studies to support its recommendation to use e-cigarettes more heavily but not in its assessment of whether e-cigarettes help smokers stop?
The net effect: Increasing harm
The evidence RCP presents on changing prevalence of smoking and e-cigarette use is consistent with the results of the meta-analyses of population studies. Results from the Smokers’ Toolkit Study (STS, Figure 3.1) and Action on Smoking and Health Survey (ASH, Figure 3.2) show larger increases in e-cigarette use than reductions in cigarette smoking. The STS data (Figure 3.1, reproduced below) show that overall nicotine use is now increasing, while ASH shows it stable (Figure 3.2, reproduced below). These trends are even more pronounced among young adults (Figures 3.7 and 3.8 in the report) and youth (Figure 3.9). The fact that e-cigarette use has increased faster than cigarette use has declined means that dual use is increasing. This increase in dual use is particularly troubling because dual use is riskier than smoking alone.
The bottom line: Even without considering the rapid uptake of e-cigarettes by youth, promotion of e-cigarettes in England is increasing, not reducing, harm.
The good news
Fortunately, clinicians are not listening to the RCP and other British e-cigarette enthusiasts and instead applying informed clinical judgement. As the RCP laments, “Despite national guidelines that clinicians should offer e-cigarettes as a treatment for tobacco dependency to their patients who smoke, a high proportion of health professionals report that they would not advise their patients to use e-cigarettes due to concerns about addiction and uncertainty about long-term harms. {Page 141]”
The RCP recognizes that England is an outlier in its approach to e-cigarettes
In the Introduction to the report, RCP recognized what an outlier England is on the e-cigarette issue:
Nevertheless, in endorsing and promoting vaping as part of a comprehensive national tobacco control programme the UK is an international outlier: few other countries have adopted this approach and none so consistently over the past 15 years. [page xiv]
The report goes so far as to say:
The RCP also understands that that the UK approach of embracing harm reduction as a complement to more conventional policy has been controversial and has attracted criticism, and does not seek to advocate that other countries should necessarily follow the UK in this approach. [Page 5, emphasis added]
Given the incomplete presentation of data – particularly omitting strong evidence that does not support its position – people outside (and inside) England would do well not to follow England’s approach.
Stanton Glantz blog 