Abstract
Objective The aim of this systematic review and meta-analysis was to assess the association between e-cigarette use and subsequent initiation or recurrence of cigarette smoking.
Data sources A systematic literature search was finalised on 11 November 2019 using PubMed (including MEDLINE), EMBASE, Cochrane Library, Scopus, PubMed Health, NICE Evidence Search, PROSPERO, CRD and PsycInfo.
Study selection Studies were included if meeting the following criteria: reporting empirical results; longitudinal observational design with a minimum of 3 months of follow-up; including general population samples; allowing for the comparison between users and nonusers of e-cigarettes. Studies rated as having high risk of bias were excluded. Studies were independently assessed by at least two authors. The procedures described by PRISMA were followed, and the quality of evidence was rated using GRADE.
Data synthesis 30 longitudinal studies from 22 different cohorts assessing e-cigarette use among nonsmokers or never-smokers at baseline, and subsequent use of cigarette smoking at follow-up, were included in this review. A random-effects meta-analysis based on 89 076 participants showed a pooled unadjusted odds ratio (OR) of cigarette smoking among baseline nonsmoker e-cigarette users compared with nonusers of 4.68 (CI 3.64–6.02), while the adjusted OR was 3.37 (CI 2.68–4.24). These results were consistent irrespective of whether the outcome was measured as ever-smoking or as past 30-day smoking. The evidence was graded as moderate.
Conclusions Use of e-cigarettes may predict the initiation or recurrence of cigarette smoking.
Abstract
This meta-analysis shows that e-cigarette use increases the risk of future initiation or recurrence of cigarette smoking, even after adjusting for potential confounders, suggesting that e-cigarette use could be considered a predictor of subsequent smoking https://bit.ly/3buMccm
Footnotes
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Author contributions: This project was initiated in collaboration between The Public Health Agency of Sweden and the SBU. All authors followed the procedures described by PRISMA when assessing studies. CR performed statistical analysis. L. Adermark drafted the manuscript, which was revised and edited by all coauthors.
Conflict of interest: L. Adermark reports grants from Swedish Research Council during the conduct of the study.
Conflict of interest: M.R. Galanti has nothing to disclose.
Conflict of interest: C. Ryk has nothing to disclose.
Conflict of interest: H. Gilljam has nothing to disclose.
Conflict of interest: L. Hedman has nothing to disclose.
Support statement: The project was under governmental support. The first author was funded by the Swedish Research Council (grant 2018-0258). Funding information for this article has been deposited with the Crossref Funder Registry.
- Received January 2, 2021.
- Accepted May 5, 2021.
- Copyright ©The authors 2021
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