Intended for healthcare professionals


Evidence about electronic cigarettes: a foundation built on rock or sand?

BMJ 2015; 351 doi: (Published 15 September 2015) Cite this as: BMJ 2015;351:h4863

Re: Evidence about electronic cigarettes: a foundation built on rock or sand?

I was invited by the BMJ to review an earlier draft of this manuscript. This published version is much improved on the authors original submission, but a number of criticisms still pertain which, in the order in which they arise in the text, are as follow:

1. McKee and Capewell are concerned that many smokers use electronic cigarettes alongside smoking (‘dual use’) rather than quitting completely. Their position is at odds with NICE guidance on tobacco harm reduction (PH45[1]) which encourages dual use not because cutting down on smoking reduces hazard (it doesn’t) but because people who do so are more likely to quit.

2. Products that deliver nicotine are effective cessation aids. That is why the UK Medicines and Healthcare Products Regulatory Agency does not require clinical trial data for new nicotine products, only evidence that they deliver nicotine. Early generation electronic cigarettes delivered low doses of nicotine. Newer devices do rather better. Those that deliver nicotine are effective.

3. The precautionary principle, in relation to treatments for smoking, requires not that alternatives to smoking are not harmful, but that they are less harmful than continued smoking. The PHE review concludes that electronic cigarettes are much less hazardous than smoking, so the recommendation that smokers use them is entirely consistent with the precautionary principle.

4. McKee and Capewell allude to serious methodological flaws in many studies of electronic cigarettes, and conflicts of interest among a proportion of authors involved in generating this evidence. However the reality is that all evidence has imperfections, and the job of the scientist is to make the best interpretation of what is available. This is what PHE has tried to do. It is true that many people researching electronic cigarettes have been funded by electronic cigarette companies to study their products, but this does not necessarily represent a conflict of interest: doing contract work for companies doesn’t invariably turn decent people into liars.

5. I share McKee and Capewell’s concerns over the funding of the MCDA study which generated the 95% estimate for harm relative to tobacco cigarettes. I was invited to take part in that study and declined for reasons that included uncertainty over this matter. However, whether the estimate of reduction in risk of 95% is valid, or whether the true figure is greater or less than 95%, matters less than the self-evident fact that long-term use of electronic cigarettes is likely to be substantially less hazardous than smoking tobacco. Encouraging smokers of tobacco cigarettes to switch to electronic cigarettes therefore makes sense.

6. Renormalisation of smoking, and gateway progression to smoking among children, are legitimate concerns. However, UK surveys are consistent in demonstrating that use of electronic cigarettes among young people is confined almost entirely to those who are already experimenting with or are regular smokers, and hence is likely to reduce rather than add to smoking uptake. There is no evidence that renormalisation is occurring.

7. From what is known of the content of electronic cigarette vapour, harm to bystanders is likely to be negligible. Discouraging use in enclosed spaces is therefore justifiable for reasons of courtesy or preference, but not on the grounds of any appreciable health risk.

8. There is no excuse for inaccurate or misleading product labels, or for failing to protect children against accidental ingestion of nicotine, but these concerns are easily remedied and should not be used to undermine the potential contribution that electronic cigarettes can make. An electronic cigarette with an inaccurate label is far less of a hazard than a tobacco cigarette.

9. The tobacco industry strongly opposes all restrictions on its business, and especially the restrictions imposed by the new EU Tobacco Products Directive (TPD [2]). That the tobacco industry chose to oppose some of the provisions for electronic cigarettes does not however mean that electronic cigarettes are bad for public health.

10. I agree that electronic cigarettes should be regulated to ensure that they are safe, and effective, and have in the past supported the view that light touch medicines regulation may be the best way to achieve that. Subsequent experience indicates however that I was wrong, and that the complexity and cost of the medicines licensing route is unsuited to the rapid development and innovation that is occurring in the nicotine market, and at present at least is counterproductive to public health. Requiring medicines licensing would remove all currently available electronic cigarettes from the market, and drive hundreds of thousands of users back to tobacco.

In my view McKee and Capewell fundamentally misunderstand the health potential of electronic cigarettes, which offer smokers, for the first time, a population-level consumer-led solution to an otherwise lethal dependence on tobacco smoking. In producing their report, PHE are attempting to ensure that an innovation with the potential to save millions of lives is capitalised upon, rather than discarded through misplaced and inappropriate precaution.


1. National Institute for Health and Care Excellence. Tobacco: harm-reduction approaches to smoking (PH45). NICE:; 2013 (accessed 12 June 2013)
2. European Parliament and Council. Directive 2014/40/EU of the European Parliament and of the Council of 3 April 2014 on the approximation of the laws, regulations and administrative provisions of the Member States concerning the manufacture, presentation and sale of tobacco and related products and repealing Directive 2001/37/EC. Official Journal of the European Union: 2014

Competing interests: I chair the Public Health England (PHE) Tobacco Control Implementation Board , co-authored a 2013 report on electronic cigarettes for PHE, chair the Royal College of Physicians Tobacco Advisory Group, and am a member of the board of trustees at Action on Smoking and Health. I am director of the UK Centre for Tobacco and Alcohol Studies.

15 September 2015
John Britton
Professor of Epidemiology
UK Centre for Tobacco and Alcohol Studie
Division of Epidemiology and Public Health , University of Nottingham, City Hospital, Nottingham NG5 1PB