The effectiveness of electronic cigarettes in smoking cessation still in question

A meta-analysis compared the results of 28 publications based on cohort studies and 8 others based on randomized studies, and concluded that the therapeutic interest of electronic cigarettes in smoking cessation remains low.

Electronic cigarettes are often presented as possible tools for smoking cessation, but their true effectiveness in this area is still debated and the many studies published on this subject are contradictory. Proponents of electronic cigarettes believe that they allow for higher abstinence rates than those obtained with nicotine replacement treatments, while their detractors consider that they do not really help with smoking cessation and that they even tend to increase nicotine dependence. A team of Swedish researchers therefore attempted to separate these points of view using a meta-analysis of the scientific literature[1].

A “low” to “very low” level of scientific evidence

The Swedish team first conducted a review of the scientific literature relating to the use of electronic cigarettes in smoking cessation. It selected 28 publications based on 26 cohort studies and 8 publications based on 7 randomized controlled studies, the inclusion criteria being the presence of a control group, follow-up for at least three months and a presentation of the results allowing the calculation of risk ratios. Cohort studies and randomized studies were treated separately. In total, the meta-analysis is based on a base of 39,147 participants.

The analysis of these publications indicates that cohort studies provide less favorable results for the role of electronic cigarettes in smoking cessation than randomized studies; cohort studies include much larger samples of the general population, while in 7 of the 8 publications on randomized studies, the group of smokers was composed only of people intending to quit smoking. Despite careful selection, methodological biases were identified in both types of studies, but appear to be more significant among cohort studies. By evaluating the level of scientific evidence in the publications, the authors note that this level of evidence can be considered very low for cohort studies and low for randomized studies. They conclude that while electronic cigarettes may be useful under certain conditions for smokers motivated to quit smoking, they are ultimately not very effective tools for smoking cessation.

The effectiveness of electronic cigarettes under debate

These conclusions are in line with those of the Scientific Committee on Health, the Environment and Emerging Risks (SCHEER, European), which estimated in April 2021 that the level of proof of the effectiveness of electronic cigarettes in smoking cessation is low, and that it is “low to moderate” for the reduction of tobacco consumption[2]. An observation which does not yet have a consensus, however, with disagreements among health professionals being numerous on the question of vaping.

In the United Kingdom, based on a study by the Cochrane review, it was accepted that electronic cigarettes could eventually be officially recognized as aids in the treatment of tobacco addiction, subject to the submission of a dossier demonstrating their potential effectiveness. Despite the enthusiasm of health authorities and certain health professionals for electronic cigarettes, divergent voices are being heard and regret that this decision is being taken in the absence of data on the long-term consequences of vaping.[3]. Epidemiologist Simon Capewell, who was initially in favour of vaping, has come out against prescribing e-cigarettes and says he "concerned by the unreserved enthusiasm on the part of public bodies whose primary duty is to protect our health"[4]. Convinced of the benefits of vaping, Robert West, professor of public health at University College London (UCL), considers it unthinkable that a health professional could “prescribe an electronic cigarette produced by a tobacco company”[5]The authors of the frequently cited Cochrane review study are more reserved than it seems about the reliability of their results; they say "moderately convinced" that electronic cigarettes are " probably " more effective than conventional nicotine substitutes, and consider that their evidence, based on a small number of studies, is "of moderate confidence, limited by imprecision"[6]The debate on the benefits of electronic cigarettes as a tool for weaning therefore seems far from being resolved.

Keywords: e-cigarette, smoking cessation, cohort studies, randomized studies ©Generation Without Tobacco

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[1] Hedman L, Galanti M, Ryk L, Gilljam H, Adermark L, Electronic cigarette use and smoking cessation in cohort studies and randomized trials: A systematic review and meta-analysis, Tob. Prev. Termination 2021;7(October):62. [2] Scientific Committee on Health, Environmental and Emerging Risks (SCHEER), Opinion on electronic cigarettes. Published on April 16, 2021, accessed on November 3, 2021. [3] Spencer B, Calver T, Vape nation: how did Britain end up so hooked on e cigarettes?, The Sunday Times (also available on the website of the SEATCA), published October 31, 2021, accessed November 3, 2021. [4] Simon Capewell, The vaping lobby are ignoring the health risks of prescribing e-cigarettes, warns SIMON CAPEWELL, The Daily Mail, published October 30, 2021, accessed November 3, 2021. [5] Expert reaction to Department of Health press release 'e-cigarettes could be prescribed on the NHS in the world first', Science Media Center, published October 29, 2021, accessed November 3, 2021. [6] Hartmann-Boyce J, McRobbie H, Butler A, Lindson N, Bullen C, Begh R, Theodoulou A, Notley C, Rigotti N, Turner T, Fanshawe T, Hajek P, Electronic cigarettes in smoking cessation (scientific summary and plain language summary), Cochrane Library, published September 14, 2021, accessed November 4, 2021. National Committee Against Smoking |