Occupational exposure to UV light and mortality from multiple sclerosis

Am J Ind Med. 2009 May;52(5):353-7. doi: 10.1002/ajim.20682.


Background: The etiology of multiple sclerosis (MS) is largely unknown; low exposure to ultraviolet (UV) light has been a suggested risk factor. The aim of this study was to investigate whether occupational exposure to UV light reduces the risk of death from MS.

Methods: The cohort was based on all individuals in the Swedish census in 1980. All MS-related deaths were identified in the national registry of causes of death. A job-exposure matrix was developed to classify the occupational exposure to UV light.

Results: MS was recorded as a cause of the death for 839 individuals. The risk of MS-related death decreased with increasing occupational exposure to UV light. The relative risk adjusted for age, sex, and socioeconomic status was 0.48 (95% CI 0.28-0.80) in the high-exposure group and 0.88 (95% CI 0.73-1.06) in the intermediate-exposure group.

Conclusions: Occupational exposure to UV light was associated with a reduced risk of MS. Our findings are corroborated by previous observations that UV light has a preventive role in the development of MS, although the possibility of reversed causality cannot be completely ruled out.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Causality
  • Cause of Death*
  • Environmental Monitoring*
  • Epidemiological Monitoring
  • Female
  • Humans
  • Male
  • Middle Aged
  • Multiple Sclerosis / etiology
  • Multiple Sclerosis / mortality*
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / statistics & numerical data*
  • Risk Factors
  • Socioeconomic Factors
  • Sweden / epidemiology
  • Ultraviolet Rays / adverse effects*
  • Young Adult