Report Endorsing e-Cigarettes Called Into Question

Liam Davenport

September 25, 2015

The evidence underpinning a report on the use of e-cigarettes that endorses their use as an effective smoking cessation aid has been questioned in an analysis that suggests that many of the claims supporting e-cigarettes lack independence.

The analysis, published online September 15 in the BMJ, notes that the debate over the harms and benefits of e-cigarettes has yet to be settled, inasmuch as their safety and effectiveness has not been established.

The original report from Public Health England (PHE), which was based on a review led by Ann McNeill, PhD, professor of tobacco addiction at King's College London, United Kingdom, stated that e-cigarettes are approximately 95% less harmful to health than tobacco cigarettes and could help people kick the smoking habit.

As reported by Medscape Medical News, Dr McNeill and colleagues found that regular users of e-cigarettes are almost exclusively adults who are already smokers, that there is no evidence that e-cigarettes are "renormalizing smoking or increasing smoking uptake," and that they are not acting as a "gateway" for young adults and adolescents.

The PHE report, which was at odds with other research, nevertheless advised caution and underlined the importance of providing balanced information.

Now, Martin McKee, MD, DSc, professor of European public health, London School of Hygiene and Tropical Medicine, and Simon Capewell, MD, PhD, DSc, professor of clinical epidemiology, Institute of Psychology, Health and Society, University of Liverpool, argue that the debate over e-cigarettes is "far from over."

"A fundamental principle of public health is that policies should be based on evidence of effectiveness. So does the available evidence show clearly that e-cigarettes are as effective as established quitting aids? Unfortunately not," they write.

They question the quality of the studies cited in the PHE report and the claim that e-cigarettes are 95% less harmful than normal cigarettes. In addition, the researchers raise doubts about the independence of the research.

They also call the claim that e-cigarettes do not act as a "gateway" for young people to begin smoking as "premature," adding: "None of the research so far can be considered conclusive, and longer term studies are needed."

The analysis sets out a series of "omissions" from the PHE report, including product safety concerns, and raises concerns over the so-called "dual" use of e-cigarettes by smokers.

"Yet perhaps its most striking feature is its consistent adoption of the most optimistic position on the limited evidence available," they write.

Heated Debate

The analysis has stirred up a heated debate, with the online version of their article generating almost 20 rapid responses so far, including several from researchers cited in the analysis.

The first response came from Dr McNeill and colleagues, who, in addition to addressing the individual points raised by Dr McKee and Dr Capewell, describe the implication that their advice was not evidence-based and free from the suspicion of influence as "offensive."

They highlight that they have an "extensive track record" of research, with hundreds of published primary research articles, and "many years" of clinical experience. Moreover, Dr McNeill and colleagues claim that "McKee and Capewell are not experts in this field," having carried out no relevant research.

Nevertheless, Dr McKee told Medscape Medical News that he believes the current evidence for the safety or effectiveness of e-cigarettes as a quitting aid is "extremely limited."

"What evidence does exist suggests that they are no more effective than nicotine patches, and there are considerable concerns about the long-term effects of inhaling a number of their constituents, especially the many food flavorings that are used. But there is also growing concern about the health effects of nicotine itself," he said.

"Until relatively recently, there was relatively little research on the long-term health effects of nicotine, because the harm associated with tar and other constituents of tobacco smoke was so clear. However, there is now growing evidence that nicotine has an adverse effects on the cardiovascular system and may promote the growth of cancers.

"For these reasons, most organizations that have reviewed the evidence have concluded that it is insufficient to recommend them as quitting aids, while noting the concerns about their safety.... In this respect, Public Health England is completely out of line with international opinion," he added.

Dr McKee believes that the question marks over the evidence for e-cigarettes has been "eclipsed by the way in which the advocates of e-cigarettes seem so remarkably unwilling to concede that there may be any problems at all."

"Indeed, they often seem to go out of their way to dismiss the many genuine concerns that others raise. We are now getting to a stage where the reasons for dismissing this evidence are themselves becoming a legitimate area of inquiry."

One way in which the knowledge gap could be plugged with more robust trials would be if e-cigarettes were regulated as medications. Does Dr McKee think that this would be beneficial?

"Given that nicotine is a pharmacologically active substance, with potential adverse effects, it seems entirely reasonable to subject it to clinical trials to determine whether it does bring the benefits that its supporters claim," he said. "This would provide the reassurance that is desperately needed."

A concern that was highlighted in the analysis was that of the potential uptake of e-cigarettes among young people, particularly children and adolescents, who would not otherwise smoke. It is less clear whether the number of these new smokers would be greater than the number of young people otherwise taking up cigarette smoking each year.

"Silent Hand" at Play?

"We simply do not know, and the evidence is conflicting, but on the basis of what evidence is available, there are certainly grounds for concern," said Dr McKee.

"What we do know is that it would be very unlikely that the tobacco industry, which now controls most of the market in electronic cigarettes, would be promoting them if they truly believed that they would be successful as a quitting aid.

"Many believe that it is more likely that they will be finely tuned to be just that little bit less attractive than real cigarettes but to allow people to retain their nicotine addiction by using them in situations where they could not smoke."

The potential "silent hand" of the tobacco industry in forming recommendations over the use of e-cigarette is a particular issue for Dr McKee.

"There have been real concerns about the role played by the tobacco industry in generating some of the evidence cited in the Public Health England report," he emphasized.

"Contrary to what has been claimed, these concerns have not been adequately investigated. Moreover, these concerns extend to many other activities linked to the promotion of electronic cigarettes.

"Unfortunately, in their responses to criticism of the Public Health England report, some supporters of electronic cigarettes have sought to dismiss concerns about conflicts of interest as if they were of no importance."

Discussing her response to Dr McKee's and Dr Capewell's analysis, Dr McNeill told Medscape Medical News that one of the issues underlying the evidence for e-cigarettes is that they are not a homogeneous product and that the market is evolving rapidly.

Indeed, the two randomized controlled trials cited in a recent Cochrane Review, which was singled out in the analysis for having flagged up the low quality of available evidence, examined e-cigarettes that were obsolete by the time the studies were published.

"We believe that the evidence would be stronger if those trials were repeated now," said Dr McNeill.

"But the problem with randomized controlled trials is that they do take 4 or 5 years to complete by the time you've got ethics and all the rest of it, so we feel in this area, with these types of products, observational studies are just as important."

"The observational study that we've reported...was a very strong study, had a very large sample size, and they tried to control for lots of possible confounders," she added.

Another Tool in the Toolbox?

Responding to criticism by Dr McKee and Dr Capewell of the claim in the original review that e-cigarettes are around 95% less harmful to health than tobacco cigarettes, Dr McNeill said: "The 95% really is a logical figure that you can come up with when you look at what's in electronic cigarettes and what comes out of them," adding that it is "a cautious measure of potential harms that may emerge over long-term use."

Dr McNeill explained: "Our reason for wanting to put a figure on it was really because, if you talk to smokers about something being less harmful, they worry about what that difference is and what that difference means."

She continued: "We felt a lot of smokers were confused about the relative risk; around a fifth thought that e-cigarettes were the same harmfulness as tobacco cigarettes, which is clearly inaccurate."

"So we're trying to redress some of these misconceptions about risk, and we used the figure that was available, but one that is entirely logical when you look at the evidence."

Addressing concerns about the influence of the tobacco industry on the evidence for e-cigarettes, Dr McNeill pointed out that initially, e-cigarettes were a niche product.

"At that point, they only way they could do that was by getting the products from the manufacturers, and in very rare cases, they took money off the e-cigarette companies," she said.

"So now, of course, they've become mainstream. We would hope researchers won't take something from the electronic cigarette manufactures," she added.

For Dr McNeill, the most important consideration is that, despite the fact that the number of smokers having fallen considerably since the 1950s and '60s, "tobacco still kills more people than about every other preventable cause of death in England."

"In advising, what we’ve got to try to do is to help the existing 18% of smokers, many of whom are very disadvantaged people, because that's where smoking is concentrated these days, to stop smoking as soon as possible.

"These people may have tried nicotine replacement, and other drugs are available. e-Cigarettes are now another tool in the box that they can use," she said.

None of the authors have disclosed any relevant financial relationships.

BMJ. Published online September 15, 2015. Abstract

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