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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

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UK report claiming e-cigs 95% safer than cigs based on one industry-linked report questions PHE's scientific credibilty

On August 19, 2015, the UK Government issued a press release with the headline “E-cigarettes around 95% less harmful than tobacco estimates landmark review” publicizing a new report commissioned by Public Health England by and led by Professor Ann McNeill (King’s College London) and Professor Peter Hajek (Queen Mary University of London), extolling e-cigarettes as a harm reduction strategy and minimizing the associated risks. It was the claim of virtual safety, however, that attracted tremendous media interest.

The report immediately spread around the world, including being widely distributed to members of the California Legislature by tobacco industry lobbyists opposing proposed legislation that would have included e-cigarettes in the state’s clean indoor air cigarette sales licensing laws.

There are many problems with the report, but the most appalling one is the conclusion, hyped in the government press release, that e-cigarettes are 95% safer than cigarettes. Rather than being based on a broad body of evidence this claim relies on a single study, Estimating the Harms of Nicotine-Containing Products Using the MCDA Approach. This paper does not contain a shred of actual evidence, but rather represents the opinions of its twelve authors (DJ Nutt, LD Phillips, D Balfour, HV Curran, M Dockrell, J Foulds, K Fagerstrom, K Letlape, A Milton, R Polosa, J Ramsey, and D Sweanor), who are harm-reduction and e-cigarette enthusiasts.

More important, as reported initially in The Lancet in its August 29 editorial on the report titled, “E-cigarettes: Public Health England’s evidence-based confusion,” and further elucidated by Martin McKee and Simon Capewell, in their paper “Evidence about electronic cigarettes: a foundation built on rock or sand?” in British Medical Journal on September 15, there are serious questions conflicts of interest for several authors of the Nutt paper.

The Lancet editorial was picked up by the London Daily Mail in an article, “E-cigarette industry funded experts who ruled vaping is safe: Official advice is based on research scientists in the pay of manufacturers,” whose title says it all.

These issues of conflict of interest, to say nothing of basing a “landmark” conclusion in e-cigarette safety on a single paper, are remarkable and call in to question the scientific credibility of Public Health England, the UK government, and everyone connected with preparing the larger report. As someone who has been involved in many government reports as both a review and as a contributor I have never seen anything like this.

The reality is that, while there is a strong consensus, including me, that e-cigarettes exposure users to fewer toxins that conventional cigarettes, precisely how dangerous they are is nowhere close to settled. For example, many of the effects of smoking (particularly in terms of heart disease) are nonlinear, with big effects at low levels of exposure and two things present in e-cigarette aerosol – ultrafine particles and strong oxidizing agents, are in e-cigarette aerosol, something not mentioned in the Nutt paper or the PHE report. The precise risks are being studied now in several laboratories around the world.

It is also important to keep in mind that e-cigarettes do not have to be all that dangerous (compared to cigarettes) to have a negative health impact at the population level. Sara Kalkhoran and I recently published “Modeling the Health Effects of Expanding e-Cigarette Sales in the United States and United Kingdom: A Monte Carlo Analysis” in JAMA Internal Medicine that evaluated the likely health impact of expanding the e-cigarette market on public health over a wide range of possible (and at this time unknown) long term health risks associated with e-cigarettes. This analysis suggested that, for one realistic possible future, the net public health impact of promoting e-cigarettes would be negative if they were more than 10% as dangerous as cigarettes and that they would and that the net health effects would be negative for other scenarios even if e-cigarettes were only 1% as dangerous as cigarettes.

The PHE report does not even consider these complexities.

As a first step to restoring its scientific credibility Public Health England should withdraw this report.

Competing interests: No competing interests

16 September 2015
Stanton A Glantz
Professor of Medicine
University of California San Francisco
San Francisco, CA