Fluctuations of MS births and UV-light exposure

Acta Neurol Scand. 2013 May;127(5):301-8. doi: 10.1111/ane.12007. Epub 2012 Sep 12.


Background: Patients with multiple sclerosis (MS) are more frequently born in spring when compared to autumn. Fluctuation of UV-light has been hypothesized to drive this phenomenon.

Aim: To assess the correlation between fluctuation of sunlight and birth season in persons with MS.

Methods: For this record-linkage study, we collected from the international MSBase and the Italian MS iMed-web databases the dates of birth of 11,415 patients with MS from 36 centres from 15 countries worldwide and compared these to dates of live-births from national registries. From all participating sites, we collected data on UV-light fluctuation and assessed its correlation with seasonal fluctuation in MS births.

Results: Compared with the reference cohort, an increased proportion of persons with MS were born in spring and a decreased proportion in autumn (odds ratio (OR) to be born in spring versus autumn = 1.158, χ² = 36.347, P < 0.001). There was no significantly increased fluctuation of MS births with increased quartile of ambient UV-light fluctuation (Ptrend = 0.086).

Conclusion: Seasonal fluctuation of MS births as found in this worldwide cohort of patients with MS did not correlate with variation in seasonal fluctuation of UV-light. Most likely, it results from a complex interplay between fluctuation of sunlight, behavioural factors, other environmental factors and (epi)genetic factors.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Databases, Factual
  • Female
  • Global Health
  • Humans
  • Male
  • Multiple Sclerosis / epidemiology*
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Registries
  • Risk Factors
  • Seasons*
  • Sunlight*
  • Ultraviolet Rays*