The effect of e-cigarettes on smoking cessation and cigarette smoking initiation: An evidence-based rapid review and meta-analysis

Ying-Ying Zhang; Fan-Long Bu; Fei Dong; Jian-Hua Wang; Si-Jia Zhu; Xiao-Wen Zhang; Nicola Robinson; Jian-Ping Liu

doi:10.18332/tid/131624

The effect of e-cigarettes on smoking cessation and cigarette smoking initiation: An evidence-based rapid review and meta-analysis

Tob Induc Dis. 2021 Jan 13:19:04. doi: 10.18332/tid/131624. eCollection 2021.

Authors

Ying-Ying Zhang¹, Fan-Long Bu^{1

2}, Fei Dong¹, Jian-Hua Wang³, Si-Jia Zhu¹, Xiao-Wen Zhang¹, Nicola Robinson^{1

4}, Jian-Ping Liu¹

Affiliations

¹ Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.
² Beijing Children's Hospital, Capital Medical University, Beijing, China.
³ Science and Technology Department, Liaoning University of Traditional Chinese Medicine, Shenyang, China.
⁴ School of Health and Social Care, London South Bank University, London, United Kingdom.

Abstract

Introduction: The contribution made by e-cigarettes to smoking cessation continues to be controversial. Reports suggest that teenagers are becoming increasingly addicted to e-cigarettes and that e-cigarette use in adolescents is associated with subsequent cigarette smoking.

Methods: Systematic searches of eleven databases were conducted (January 2015 to June 2020). Systematic reviews, randomized controlled trials (RCTs) and cohort studies comparing e-cigarettes with placebo e-cigarettes, nicotine replacement therapy (NRT) or no e-cigarette use were included. The two primary outcomes were smoking cessation among smokers and smoking initiation among non-smoking teenagers. The secondary outcome was adverse events. Data were synthesized using risk ratio (RR) or adjusted odds ratio (AOR) with 95% confidence interval (CI).

Results: Six systematic reviews, 5 RCTs and 24 cohort studies were identified. For smoking cessation, findings from 4 systematic reviews indicated that e-cigarettes contributed to cessation while one found the opposite. Meta-analysis of 5 RCTs suggested that e-cigarettes were superior to NRT or placebo for smoking cessation (RR=1.55; 95% CI: 1.00-2.40; I²=57.6%; low certainty; 5 trials, n=4025). Evidence from 9 cohort studies showed that e-cigarette use was not associated with cessation (AOR=1.16; 95% CI: 0.88-1.54; I²=69.0%; n=22220). Subgroup analysis suggested that intensive e-cigarette use may be associated with cessation. In terms of smoking initiation, adolescents who ever used e-cigarettes had a greater risk for smoking initiation than non-users (AOR=2.91; 95% CI: 2.61-3.23; I²=61.0%; 15 trials, n=68943), the findings were consistent with one included systematic review. No serious adverse events were reported in the included studies.

Conclusions: Low certainty evidence suggests that e-cigarettes appear to be potentially effective for smoking cessation. The use of e-cigarettes in adolescents may be associated with smoking initiation. No serious adverse events were reported.

Keywords: e-cigarettes; rapid review; smoking cessation; smoking initiation; systematic review.

Publication types

Review