Background

Since December 2014, the Cochrane Collaboration (Cochrane) has published an annually updated systematic review titled Electronic cigarettes for smoking cessation^[1]. The review “examines the effectiveness, tolerability, and safety of using electronic cigarettes (ECs) to help people who smoke tobacco achieve long-term smoking abstinence”.

Cochrane published the 5th update on 17 November 2022. This update included 78 completed studies, representing 22,052 participants, of which 40 were randomised controlled trials (RCTs). 17 of the 78 included studies were new in this update.

Findings

Overall, the authors determined there is now high-certainty evidence that ECs with nicotine increase quit rates compared to nicotine replacement therapy (NRT) – up from moderate-certainty in the September 2021 review – and moderate-certainty evidence that they increase quit rates compared to ECs without nicotine. Evidence comparing nicotine EC with usual care/no treatment also suggests benefit, but is less certain.

• People are more likely to stop smoking for at least six months using nicotine EC than using NRT (6 studies, 2378 people), or EC without nicotine (5 studies, 1447 people).
• Nicotine EC may help more people to stop smoking than no support or behavioural support only (7 studies, 3126 people).
• For every 100 people using nicotine EC to stop smoking, 9 to 14 might successfully stop, compared with only 6 of 100 people using NRT, 7 of 100 using EC without nicotine, or 4 of 100 people having no support or behavioural support only.

The authors found no difference in adverse events (AEs) between nicotine and non-nicotine ECs nor between nicotine ECs and NRT. The overall incidence of severe AEs was low across all study arms and the authors found no evidence of serious harm from nicotine EC.

The authors noted the need for more evidence, particularly about the effects of newer types of EC that “have better nicotine delivery than older types of EC, as better nicotine delivery might help more people quit smoking.”

Expert Commentary

“Smoking is the leading cause of premature death and disability, and a powerful driver of health inequality. There are still more than 6 million people in the UK who smoke, and these findings strongly support making e-cigarettes available as one of the options to help them to quit. Smoking cessation services can continue to be confident supporting smokers to switch to e-cigarettes.”

Prof. Nicholas Hopkinson, Professor of Respiratory Medicine and Honorary Consultant Physician, National Heart and Lung Institute, Imperial College

“With more data than ever before, the authors concluded that there is now high-certainty evidence that e-cigarettes are more effective in helping people to quit that traditional NRT… These findings follow a recent review of the harms of e-cigarettes, which showed clear evidence that vaping poses only a small fraction of the health risks of smoking. Taken together, these reports should provide reassurance to smokers that e-cigarettes are much safer to use and can increase your chances of quitting.”

Dr. Sarah Jackson, Principal Research Fellow, UCL Tobacco and Alcohol Research Group

“This comprehensive evidence review confirms, once again, that nicotine e-cigarettes help smokers to quit smoking; and that these products are more effective than medically licensed NRT. All smokers should therefore try vaping as a means to end their dependency on smoking tobacco.”

Prof. John Britton, Emeritus Professor of Epidemiology, University of Nottingham

Limitations of current research

The representation of the current generation of ECs is limited due to the amount of admissible independent research conducted and the lag in publication after it is conducted. This is critical because EC technology has innovated rapidly in the last decade. Furthermore, caution should be exercised in generalising these findings to other contexts, such as Australia’s, since the research was conducted on a heterogeneous range of products marketed under consumer product regulations.

None of the products studied were developed or marketed for smoking cessation purposes, yet they still demonstrate impressive efficacy when used for smoking cessation purposes. It is plausible, if not likely, that the current generation of products will demonstrate even higher effectiveness when dispensed under medical supervision under Australia’s medical regulations.

^{[1] Hartmann-Boyce J, Lindson N, Butler AR, McRobbie H, Bullen C, Begh R, Theodoulou A, Notley C, Rigotti NA, Turner T, Fanshawe TR, Hajek P. Electronic cigarettes for smoking cessation. Cochrane Database of Systematic Reviews 2022, Issue 11. Art. No.: CD010216. DOI: 10.1002/14651858.CD010216.pub7. Accessed 21 November 2022.}