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There is increasing evidence that smoking is a significant risk factor in MS.

MS seems to be caused by a combination of genetic susceptibility combined with one or more environmental factors. There is evidence that infection with a virus, particularly Epstein Barr virus (EBV), and lack of vitamin D are involved. However, smoking may also be a risk factor as the combined analysis of 14 research studies, involving 3,052 people with MS and 457,619 controls, showed that a history of smoking was associated with an increased risk of MS.

Analysis of four studies that looked at the effect of smoking on progression of MS was less certain, as it fell just short of statistical significance.

A British study looked at the risk of reaching EDSS scores in 895 people with MS, half of whom had been smokers at the time of diagnosis. People who continued to smoke had a higher risk of reaching EDSS 4 and EDSS 6 than non-smokers. There was no significant difference in risk between non-smokers and people who had stopped smoking.

Smoking is a risk factor for a range of other conditions including lung cancer and other autoimmune conditions. It can also produce shortness of breath, susceptibility to lung infections and heartbeat irregularities which could result in an increase in disability for a person with MS.


  • Handel AE, et al. Smoking and multiple sclerosis: an updated meta-analysis. PLoS One 2011;6(1):e16149. Full article
  • Manouchehrinia A, et al. Tobacco smoking and disability progression in multiple sclerosis: United Kingdom cohort study. Brain 2013;136(7):2298-2304 Full article
  • Marrie RA, et al. Smokers with multiple sclerosis are more likely to report comorbid autoimmune disease. Neuroepidemiology 2011;36(2):85-90. Full article

Last updated: 13 August 2014
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