Tobacco smoking and multiple sclerosis: a systematic review of systematic and narrative reviews of observational studies
The aim of this review was to systematically review systematic and narrative reviews of observational studies published on the relation between tobacco smoking and multiple sclerosis (MS).
Subjects and methods
A systematic search of the literature in PubMed and Scopus was conducted in June 2016. Two authors independently reviewed the search results and extracted key points. Review studies (i.e., review, systematic, narrative, or meta-analysis) that reported on smoking and MS were selected. The methodological quality of included systematic reviews and meta-analyses was assessed using the AMSTAR checklist. The methodological quality of narrative reviews was evaluated using a seven-item measure developed by the authors.
Seventeen reviews met the inclusion criteria and were categorized as either systematic reviews or narrative reviews. Smoking was associated with increased risk of MS for ever- compared with never-smokers and current compared with non-smokers. The summary odds ratio of MS for ever-smokers versus never-smokers varied between 1.40 (95% CI: 1.29–1.52) and 1.46 (95% CI: 1.33–1.59).
This review of reviews identifies smoking as a risk factor for MS susceptibility. However, more research is needed to conclusively establish the mechanisms driving this association.
KeywordsTobacco Smoking Multiple sclerosis Systematic review
We thank Tyra Lagerberg for her thoughts and comments and for improving the use of English in the manuscript.
Compliance with ethical standards
This article does not contain any patient data; thus, ethical approval was not required for this study.
Conflict of interest
The authors declare that they have no conflict of interest.
This study did not receive any funding.
- Jafari N (2012) Risk factors in cause and course of multiple sclerosis. Naghmeh JafariGoogle Scholar
- La Torre G, Backhaus I, Mannocci A (2015) Rating for narrative reviews: concept and development of the International Narrative Systematic Assessment tool. https://www.researchgate.net/publication/280098483_Rating_for_narrative_reviews_concept_and_development_of_the_International_Narrative_Systematic_Assessment_tool. Accessed 18 Jan 2017
- Poorolajal J, Bahrami M, Karami M, Hooshmand E (2016) Effect of smoking on multiple sclerosis: a meta-analysis. J Public Health. doi: 10.1093/pubmed/fdw030
- Shea BJ, Grimshaw JM, Wells GA, Boers M, Andersson N, Hamel C, Porter AC, Tugwell P, Moher D, Bouter LM (2007) Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews. BMC med res Methodol 7:10. doi: 10.1186/1471-2288-7-10 CrossRefPubMedPubMedCentralGoogle Scholar
- Simon KC, Van der Mei IAF, Munger KL, Ponsonby A, Dickinson J, Dwyer T, Sundström P, Ascherio A (2010) Combined effects of smoking, anti-EBNA antibodies, and HLA-DRB1* 1501 on multiple sclerosis risk.Neurology 74(17):1365–1371. doi: 10.1212/WNL.0b013e3181dad57e
- World Health Organization (2008) Atlas multiple sclerosis resources in the world 2008. Accessed 10 June 2016Google Scholar