title: Environmental risk factors in multiple sclerosis.
abstract: OBJECTIVE
  Multiple sclerosis (MS) likely results from an interaction between genetic and exogenous factors. While genetics shapes the overall population MS susceptibility, observed epidemiological patterns strongly suggest a role for the environment in disease initiation and modulation.
  
  
  RESULTS
  Findings from studies on seasonality in MS patients' birth, disease onset and exacerbations, as well as apparent temporal trends in incidence and gender ratio support an influential effect of viruses, metabolic and lifestyle factors on MS risk. Epstein-Barr virus, vitamin D status, and smoking are factors that may explain such epidemiological patterns.
  
  
  CONCLUSIONS
  Further epidemiological investigations are encouraged and opportunities to use data from existing cohort studies as well as the design of new studies should be pursued. In particular, the development of new large multicentre population-based case-control studies which incorporate the study of the role of environment and genetics, including epigenetic mechanisms, in determining MS risk is proposed.
authors.affiliation: Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway. maura.pugliatti@isf.uib.no
authors.forename: M
authors.initials: M
authors.lastname: Pugliatti
authors.forename: H F
authors.initials: HF
authors.lastname: Harbo
authors.forename: T
authors.initials: T
authors.lastname: Holmøy
authors.forename: M T
authors.initials: MT
authors.lastname: Kampman
authors.forename: K-M
authors.initials: KM
authors.lastname: Myhr
authors.forename: T
authors.initials: T
authors.lastname: Riise
authors.forename: C
authors.initials: C
authors.lastname: Wolfson
mesh_terms: D004032:Diet; D004777:Environment; D006801:Humans; D008019:Life Style; D009103:Multiple Sclerosis / Q000209:etiology*; D012307:Risk Factors