E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis. Issue 3 (30th March 2021)

• Record Type: Journal Article
• Authors: Baenziger, Olivia Nina; Ford, Laura; Yazidjoglou, Amelia; Joshy, Grace; Banks, Emily
• Is Part Of: BMJ open. Volume 11:Issue 3(2021)
• Publication Date: 2021-03-30
• Subjects: epidemiology -- public health -- respiratory medicine (see thoracic medicine); Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2020-045603
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objective: To review and summarise the current evidence on the uptake of combustible cigarette smoking following e-cigarette use in non-smokers—including never-smokers, people not currently smoking and past smokers—through an umbrella review, systematic review and meta-analysis. Design: Umbrella review, systematic review and meta-analysis. Data sources: PubMed, Scopus, Web of Science, PsychINFO (Ovid), Medline (Ovid) and Wiley Cochrane Library up to April 2020. Results: Of 6225 results, 25 studies of non-smokers—never, not current and former smokers—with a baseline measure of e-cigarette use and an outcome measure of combustible smoking uptake were included. All 25 studies found increased risk of smoking uptake with e-cigarette exposure, although magnitude varied substantially. Using a random-effects model, comparing e-cigarette users versus non-e-cigarette users, among never-smokers at baseline the OR for smoking initiation was 3.25 (95% CI 2.61 to 4.05, I 2 85.7%) and among non-smokers at baseline the OR for current smoking was 2.87 (95% CI 1.97 to 4.19, I 2 90.1%). Among former smokers, smoking relapse was higher in e-cigarette users versus non-users (OR=2.40, 95% CI 1.50 to 3.83, I 2 12.3%). Conclusions: Across multiple settings, non-smokers who use e-cigarettes are consistently more likely than those avoiding e-cigarettes to initiate combustible cigarette smoking and become current smokers. The magnitude of this risk varied, with an average of around three times the odds. Former smokers using e-cigarettes have over twice the odds of relapse as non-e-cigarettes users. This study is the first to our knowledge to review and pool data on the latter topic. PROSPERO registration number: CRD42020168596.