Eurobarometer survey and e-cigarettes: unsubstantiated claims

Abstract

Sir—We read with interest the paper written by Farsalinos and colleagues suggesting a role for e-cigarettes in smoking cessation and reduction among Europeans based on a cross-sectional survey 1. They claim: ‘Extrapolating to the whole European Union (EU) population, an estimated 6.1 million European have quit smoking with the use of e-cigarettes, while a further 9.1 million have reduced their smoking consumption’ 1. This could be interpreted easily as a causal statement, and indeed this is how it has been construed in news outlets 2. However, neither the cross-sectional nature of the study nor the way that survey questions were formulated support such statements. First of all, it is impossible to know how many of those who claim that they have stopped with the aid of e-cigarettes would have stopped anyway, and how many of those who used an e-cigarette but failed to stop would have stopped had they used another method. That is why researchers go to great lengths to compare quitting rates in randomized controlled trials (RCTs) and observational studies. Secondly, the study's key question (‘Did the use of electronic cigarettes or any similar device help you to stop or reduce your tobacco consumption?’) is overly crude and can lead to mislabeling of short cessation periods as cessation. Some of the heavier smokers may count short periods of non-smoking as total success, while the more occasional smokers may underestimate the difficulty of remaining quit longer term, both contributing potentially to higher reporting of quitting success. Moreover, given the charged atmosphere about e-cigarette regulations in the EU 3-5, such a leading question can persuade some e-cigarette users to report a positive effect on cessation/reduction in the hope of less strict regulations of e-cigarettes 6, 7. This question, furthermore, excludes those who use e-cigarettes for reasons other than quitting or reducing smoking (e.g. smoking where conventional cigarettes are not allowed), thus contributing to the selectiveness of certain responders/responses and subsequently biased conclusions based on these responses. Unsubstantiated claims based on weak evidence can lead only to more confusion about the potential role of e-cigarettes in tobacco control. None.