Physicians for a Smoke-Free Canada – November 21, 2019.
There are thousands of scientific studies on tobacco use published every month (38,000+ so far this year!), but only a few find their way into the mainstream media. Among those, even fewer seem to have real influence on government policies.
In many circles, one of the most influential papers this year was a British study on the effectiveness of e-cigarettes at helping smokers quit. Psychologist Dr. Peter Hajek and his colleagues used the “gold standard” methods of a randomized clinical trial to compare E-cigarettes (consumer products) against NRT (licensed therapies) at as cessation products.
The results of this study were published in the New England Journal of Medicine in January and immediately reported by media outlets across the world. Time magazine said the study showed “E-Cigs More Effective Than Nicotine Replacements in Helping Smokers Quit”, a messages echoed in many Canadian media outlets.
The idea that e-cigs are twice as good at helping smokers quit as NRT has now taken root.
Indeed, it seems to have become part of the tobacco control belief system. This study has been cited in policy discussions as a reason that governments should continue to allow e-cigarette promotions.
Differing points of view
Yet Dr. Hajek and his team are not the only highly qualified researchers looking into this issue, and theirs is not the only scientific conclusion on offer.
Among other respected public health scientists who have looked at the efficacy of e-cigarettes as cessation products are those at the World Health Organization. This summer, after considering Dr. Hajek’s results and others, the WHO concluded: “Although some [Electronic nicotine delivery systems] have been shown to help smokers quit conventional smoking under certain conditions, when used as NRTs the scientific evidence is inconclusive. There have only been a limited number of randomized control trials and longitudinal studies investigating the role of ENDS as potential cessation aids offered to a population, and their conclusions are equivocal.”
This is not the only time that Dr. Hajek and the World Health Organization have come to starkly different conclusions about interpreting research findings. In 2014, Dr. Hajek was among a research team which openly criticized the WHO and which accused it of “misleading” the public with the statements like the following: “Youth are rapidly adopting e-cigarettes”, “the hope that e-cigarettes will reduce harm by delivering ‘clean’ nicotine will not be realized in continuing dual users” and “E-cigarettes deliver lower levels of toxins that conventional cigarettes, but they still deliver some toxins.”
Nor is this the first time that Dr. Hajek has nailed his colours to the mast of e-cigarettes as benefit to public health. He was part of a scientific team that advised Public Health England to say that e-cigarettes were “95% safer” than combustible cigarettes. Canada’s Heart and Stroke Foundation and The Lancet are among the many who have strongly criticized this statement.
A second look at the outcomes of Dr. Hajek’s experiment.
The data presented in the table above is drawn from the broad range of outcomes from Dr. Hajek’s study, including those reported in the NEJM paper and also in a NIHR Health Technology Assessment report published in August:
NRT performed twice as well as E-cigs at achieving nicotine abstinance.
From this table, we can say that:
Other important conclusions can also be drawn from these outcomes:
Higher standards of evidence
Single clinical trials, no matter how well performed or reported, are not usually considered the strongest evidence base for decision making. That distinction is usually reserved for systematic reveiws of multiple studies
In 2016 two systematic reviews of e-cigarettes as cessation aids were conducted. They did not come to the same conclusion.
One was conducted as a Cochrane review (in which Dr. Hajek participated as a reviewer.) This panel focused on the results of 2 randomized clinical trials, and concluded that “There is evidence from two trials that ECs help smokers to stop smoking in the long term compared with placebo ECs.” The quality of those studies was considered low, and Dr. Hajek’s 2019 results will likely strengthen this conclusion in subsequent Cochrane reviews.
The other was a systematic review and meta analysis conducted by U.S. physician Dr. Sara Kalkhoran and Dr. Stanton Glantz. They looked over the same literature field, and included some of the same studies as the Cochrane review, including the same 2 clinical trials. In addition, they considered the results of 20 studies with control groups and other studies. The conclusions from this analysis were that rather than helping smokers quit, e-cigarettes made it harder for them to do so. The “odds of quitting cigarettes were 28% lower in those who used e-cigarettes compared with those who did not use e-cigarettes.”
A Canadian study involving more than 6,000 smokers was included in the Kalkhoran review, but not by the Cochrane team. It was conducted at CAMH, and eventually published bothas a conference paper and as a journal article. In this Ontario study, would-be quitters who used e-cigarettes were less likely to succeed in quitting. “E-cig adoption seems to negatively affect cessation outcomes and provides no benefit as a harm reduction tool …”
This year researchers at the Ontario Tobacco Research Unit published a review of “E-Cigarette Use for Smoking Cessation.” They found “a wide range of results” and – while clearly open to the idea of using vaping as a cessation tool – nontheless reported that “In general, the scientific literature regarding the effectiveness of e-cigarettes as a smoking cessation aid remains inconclusive.”
The Montreal Jewish General is leading a clinical trial on e-cigarettes as cessation devices, partnersing with several hospitals across Canada. Their results are not expected until next year.
Data from another Canadian random clinical trial (on a smoking-cessation smart phone app) was re-analyzed to compare the results of participants who used e-cigarettes. As Public Health Ontario reported, – “Dual users who continued to vape with ecigarettes for longer duration were less likely to quit tobacco than non users, despite reported high levels of confidence to quit.” The scientist conducting this RCT concluded “Despite claims by the industry, [vaping is] not a panacea for helping smokers quit tobacco.”
Setting policy or clinical practice guidelines on the role of e-cigarettes is challenging in the messy real world of competing evidence, uncertainty, nuance and concious/unconcious bias. And that is before commercial influence and tobacco industry interference is added to the mix!
Currently, smokers who want to quit smoking have a variety of tools available to them, including a variety of licensed NRT therapies, non-licensed e-cigarettes, as well as proven and unproven behavioural supports that range from telephone counselling to hypnotherapy. None of the above has been the choice of most successful quitters.
Smokers (and those who pay for quitting programs) are entitled to know the benefits and the risks of the approaches on offer. In the case of e-cigarettes, Dr. Hajek’s paper is presented as evidence that E-cigarettes are a better option than NRT. The same paper also provides evidence that NRT is a better option for those who want to overcome addiction and also for those who want to avoid the additional risks of dual use.
Physicians for a Smoke-Free Canada – November 21, 2019.