The effects of smoking and vaping on multiple sclerosis onset and disease progression: An umbrella review
Abstract
BACKGROUND
Tobacco smoking has been implicated in multiple sclerosis (MS) onset and progression. However, findings are dispersed across reviews with differing quality and scope.
OBJECTIVES
This umbrella review synthesised systematic reviews to provide a comprehensive overview of evidence, knowledge gaps, and inform future research about the effects of exposure to combustible tobacco and the use of e-cigarettes/heated tobacco products on MS onset and progression.
METHOD
We searched CINAHL, Embase, MEDLINE, Web of Science, Cochrane and Epistemonikos for reviews published between 2014 and March 2025. Two independent reviewers assessed eligibility, extracted data, and evaluated risk of bias using the Risk Of Bias In Systematic Reviews (ROBIS) tool. This study was prospectively registered (Prospero: CRD420251033269).
RESULTS
Eleven systematic reviews, encompassing 97 unique studies, were included. Nine systematic reviews assessed MS onset and six assessed progression. Active cigarette and waterpipe smoking were consistently associated with an increased risk of MS onset, with some evidence of a dose-response relationship. Findings for passive cigarette smoking were mixed. No association was found between prenatal smoking and MS risk. Smoking was associated with a higher risk of disability progression and progression to secondary progressive MS, particularly with higher pack-years, though findings varied. Evidence on the effects of waterpipe and prenatal smoking on MS progression,…
How strong is the evidence?
Evidence Hub reads this as a systematic review, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.
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