Risk of smoking relapse with the use of electronic cigarettes: A systematic review with meta-analysis of longitudinal studies.

Introduction:
This text is a summary of a systematic review and meta-analysis published in the European Network for Smoking and Tobacco Prevention (ENSP) by Barufaldi et al. The review aimed to identify and summarize longitudinal studies evaluating the risk of smoking relapse using e-cigarettes by former smokers. The study methodology and eligibility criteria were prespecified and submitted for registration at the PROSPERO database. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines.

Key Points:

* The review identified six studies that met the eligibility criteria and were included in the qualitative synthesis.
* The studies were conducted in the USA, UK, and France, with final sample size varying from 374 to 4094 former smokers.
* Risk of relapse was 2.03 (95% CI: 1.39--2.96) among former smoker users than non-users of e-cigarettes.
* Long-term former smokers were the main contributors for the higher relapse risk.
* The impact of frequency of exposure to e-cigarettes (past, non-daily, daily) was uncertain.
* The meta-analysis considered three categories of e-cigarette exposure: experimentation or previous use, current occasional or non-daily use, and current regular or daily use.
* The statistical heterogeneity between the studies was high (I^2 test).

Main Message:
The study highlights the potential risks of e-cigarette use in former smokers, who may have a higher risk of smoking relapse. The findings suggest that long-term former smokers are the main contributors to this higher relapse risk. However, the impact of frequency of exposure to e-cigarettes (past, non-daily, daily) remains uncertain. Therefore, it is crucial to regulate e-cigarettes carefully to minimize the risks and protect public health. The study emphasizes the need for further research to understand the long-term effects of e-cigarette use on smoking relapse.

Barufaldi LA, Guerra RL, de Albuquerque R de CR, et al. Risk of smoking relapse with the use of electronic cigarettes: A systematic review with meta-analysis of longitudinal studies. Tobacco prevention & cessation. 2021;29:29. doi:10.18332/tpc/132964