A study recently published online in the journal Nicotine & Tobacco Research purports to show that the use of e-cigarettes inhibits smoking cessation. In the study, smokers were recruited from 187 primary care clinics in Ontario. Some of these smokers had not used e-cigarettes and some were dual users (of both cigarettes and e-cigarettes). The study followed these smokers for six months and found that the smoking cessation rate among the non-e-cigarette-users was significantly higher than among the dual users. Based on this finding, the paper concludes that e-cigarette use inhibits smoking cessation.
The paper's conclusion is as follows: "This study confirms previous findings from observational studies regarding the negative
association between e-cigarette use
and smoking cessation, but in a large cohort of
smokers enrolled in an evidence-based treatment program. The
of these findings are that concurrent use of
e-cigarettes during a quit attempt utilizing cost-free evidence-based
(nicotine replacement therapy plus behavioural
counselling) does not confer any added benefit and may hamper successful
The Rest of the Story
The major flaw in this study is that it is very likely that the smokers who were dual users became dual users because they were unable to quit smoking. Had they been successful in quitting smoking, they would not have become dual users (and thus their success would not have been observed in the study). This means that what the study is really comparing is smoking cessation rates among smokers who have failed to quit versus those who have not necessarily failed to quit. It would be shocking if the study did not find higher quit rates among the non-dual users.
While the study controlled for confidence in ability to quit using a crude measure, this is clearly not as sensitive a measure as whether the person had actually failed to quit smoking, which is of course going to be much more productive than any self-reported attitudinal measure. Apparently, one question that was not asked of study subjects was their history of failed quit attempts. And another important question that was not asked was whether or not the subjects had previously tried NRT and failed. Without either of these two variables, the study was unable to control for the sampling bias that is inherent in this study design.
Most smokers who use e-cigarettes for cessation are doing so specifically because they failed to quit using traditional methods in the past and/or because they don't think they can (or don't want to) completely eliminate nicotine or the "smoking" behavior. On top of this, of these smokers, it is only the ones who fail to quit who become dual users. Skimmed off the top are all the successful quitters who, according to this study, do not exist. Their experiences are not considered at all in the analysis of whether or not e-cigarettes can help smokers quit.
Moreover, smokers who try e-cigarettes are likely to have failed in previous quit attempts using NRT. Having a history of failed quit attempts using NRT is obviously a very strong predictor of future failure to quit using NRT. Many of the dual users who were given NRT probably knew that it was a waste of time, since they did not previously find this method useful. In our focus groups with vapers, we found that nearly all of them chose to try e-cigarettes because they were unhappy with, and unsuccessful with the FDA-approved cessation strategies, such as NRT.
What could explain such a biased interpretation of the study results?
Unfortunately, two of the major authors of the article have significant conflicts of interest with Big Pharma, leading to the appearance that these conflicts might have been associated with the apparent bias in the interpretation and reporting of the study findings and conclusions.
Both the lead author and the senior author of the study disclosed that they have received funding from Pfizer. The senior author also disclosed having received honoraria and consulting fees from Johnson & Johnson, Pfizer, and NABI Pharmaceuticals.
These are significant conflicts of interest because all of these pharmaceutical companies are developing or marketing smoking cessation products. They stand to lose financially if e-cigarettes are found to be effective cessation products. Therefore, these conflicts of interest create an appearance that the apparent bias in the interpretation of study results and in the design of the study itself may be related to financial interests in these pharmaceutical companies.
A more detailed summary of the conflicts of interest of the senior author reveals a host of financial interests related to pharmaceutical companies: "He has received funds from Schering Canada to provide buprenorphine
training (2000). He has acted as a paid consultant for Johnson and
Johnson Consumer Health Care Canada; Pfizer Inc. Canada; Pfizer Global;
Sanofi-Synthelabo, Canada; GlaxoSmithKline, Canada; Genpharm and
Prepharm Canada; NABI Pharmaceuticals: V-CC Systems Inc. & EHealth
Bahaviour Change Software Co.; and Schering Canada. He has also received honoraria or been part of a speakers bureau for
Schering Canada; Johnson and Johnson Consumer Health Care, Canada,
Pfizer Inc. Canada; Pfizer Global; Sanofi-Synthelabo Canada; Glaxo Smith
Kine Canada; Genpharm & Premfarm Canada and NABI Pharmaceuticals."
There is a real need for clinical research on the effectiveness of electronic cigarettes that is conducted by unconflicted investigators. I do not believe that much of the work done by conflicted investigators can be trusted because it has been improperly designed in a way that has introduced serious sampling bias which has not been adequately accounted for. At some institutions, including my own, investigators with conflicts of interest like this are not allowed to conduct this kind of research in the first place. Seeing the problems apparent in work like the present study, these policies may be appropriate.