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?

McNeill and colleagues claim that we “are not experts in this field” but by defining “this field” as smoking cessation they highlight the major problem with their approach to this issue. Tobacco control requires a comprehensive policy, involving an understanding of the epidemiology of the most powerful smoking, population-level effective measures (such as controls on Affordability, Availability and Acceptability) and, crucially, the role of the tobacco industry in reframing the terms of the debate and in delaying or blocking these measures. It is our extensive experience researching these areas that we brought to the debate, as well as our population-level perspective. From this perspective, comparing vaping only to smoking is indeed a “narrow focus”. For the majority of adults and children, the correct comparison is with breathing fresh air. We must therefore not ignore young people who are initiated into vaping but who otherwise would not be addicted to nicotine.

McNeill and colleagues state that responses to “our earlier accusations and inaccuracies have been published”. The references they cite imply that we were authors of a Lancet editorial that also criticised their report.[1] For the avoidance of doubt, we were not and the Guardian, which initially reported this, has now issued a correction.[2] However, they fail to acknowledge that we, in turn, responded to their response to the Lancet editorial, detailing their failure to address some of the key concerns that the Lancet raised.[3]

They claim that the concerns about industry funding and conflict of interest have been addressed elsewhere. This is simply not the case. The reference they give is to a statement by the lead author of the study in question [4] which does not mention the evidence raising concerns that are already in the public domain, and to which we refer to in our paper. Specifically, the questions about the funding of EuroSwiss Health and related companies remain unaddressed. We note that Britton was sufficiently concerned about this not to participate in the panel that generated the 95% safer figure. Britton also notes that some of the researchers have been funded by e-cigarette manufacturers. We are thus very concerned that a number, including some on the Nutt et al. paper, have also been funded by the transnational tobacco industry, whose behaviour with respect to science is surely no longer in doubt.

We invite readers to search their report [5] for the term “dual use” and decide which of us is right. However, in one of the few places where they do mention it they note “data are needed on the natural trajectory of ‘dual use’, ie whether dual use is more likely to lead to smoking cessation later or to sustain smoking.” We agree, but struggle to reconcile this statement and other evidence with their claim that “most of them [dual users] are trying to stop smoking.”

They argue that “the key chemicals present in EC only are not expected to pose serious health risks”. However, the long term effects of inhaling these many hundreds of substances on a daily basis have never been evaluated. We would suggest that the public needs slightly more explanation.

McNeill et al argue that evidence of a gateway effect has not yet been seen in Great Britain, yet fail to report worrying evidence emerging from North America. We note how, in their report, they go to considerable lengths to question whether the concept of a gateway effect has any meaning, so we welcome how they now seem to accept that it may be a concern. However, our argument is that it is too early to know if this is happening, particularly considering that the evidence from elsewhere to justify our concerns.

Britton notes that he reviewed an earlier version of our paper. We welcomed his critical comments and responded at length to them. We agree that this improved the final paper, although there was no need to change the core elements. Furthermore, peer review remains the foundation of scientific progress. It would therefore be reassuring to know more about the review process conducted for the McNeill et al.[6] and Public Health England reports.

1. Lancet. E-cigarettes: Public Health England's evidence-based confusion. Lancet 2015; 386: 829.
2. Boseley S. Public Health England under fire for saying e-cigarettes are 95% safer. Guardian.
3. McKee M, Capewell S. Electronic cigarettes: we need evidence, not opinions. Lancet 2015; doi: 10.1016/S0140-6736(15)00146-4.
4. Nutt DJ, Phillips LD, Balfour D, et al. Estimating the harms of nicotine-containing products using the MCDA approach. European addiction research 2014;20(5):218-25.
5. McNeill A, Brose LS, Calder R, et al. E-cigarettes: an evidence update: A report commissioned by Public Health England. London: Public Health England, 2015.
6. Glantz S. UK report claiming e-cigs 95% safer than cigs based on one industry-linked report questions PHE's scientific credibility.

Competing interests: we are authors of the paper being criticised in the first 2 rapid responses

16 September 2015
Martin McKee
Professor of European Public Health
Professor Simon Capewell, University of Liverpool
London School of Hygiene and Tropical Medicine
15-17 Tavistock Place