Impact of the environment on multiple sclerosis

Tidsskr Nor Laegeforen. 2015 May 19;135(9):856-60. doi: 10.4045/tidsskr.14.0751.
[Article in English, Norwegian]


Background: Epidemiological studies suggest that environmental factors play a significant role in the development of multiple sclerosis. This article presents current knowledge on the impact of the environment on disease risk and disease course.

Method: We have conducted searches in PubMed for «multiple sclerosis» combined with «environment» as well as relevant environmental factors.

Results: It is highly likely that an interaction between genetic and environmental factors determines who will develop multiple sclerosis. Epstein-Barr virus infection, smoking, and low vitamin D levels are the environmental factors that have shown the strongest and most consistent association with development of the disease. Low vitamin D levels are also associated with high disease activity. Other risk factors include obesity and high salt intake.

Interpretation: Although epidemiological studies have identified a number of environmental factors with potential aetiological relevance, and the importance of these is supported by experimental studies, there is still insufficient evidence to establish a causal role for these factors in multiple sclerosis.

Publication types

  • Review

MeSH terms

  • Environmental Exposure / adverse effects*
  • Epstein-Barr Virus Infections / complications
  • Epstein-Barr Virus Infections / physiopathology
  • Humans
  • Lymphocytes / physiology
  • Multiple Sclerosis / etiology*
  • Multiple Sclerosis / physiopathology
  • Obesity / complications
  • Risk Factors
  • Smoking / adverse effects
  • Smoking / physiopathology
  • Sodium Chloride, Dietary / adverse effects
  • Sodium Chloride, Dietary / metabolism
  • Vitamin D Deficiency / complications
  • Vitamin D Deficiency / physiopathology


  • Sodium Chloride, Dietary