title: The EnvIMS Study: Design and Methodology of an International Case-Control Study of Environmental Risk Factors in Multiple Sclerosis.
abstract: BACKGROUND
  Multiple sclerosis (MS) is a chronic disease of the central nervous system, often resulting in significant neurological disability. The causes of MS are not known; however, the incidence of MS is increasing, thereby suggesting that changes in lifestyle and/or environmental factors may be responsible. On this background, the Environmental Risk Factors in MS Study or EnvIMS study was designed to further explore the etiology of MS. The design and methodology are described, providing details to enable investigators to (i) use our experiences to design their own studies; (ii) take advantage of, and build on the methodological work completed for, the EnvIMS study; (iii) become aware of this data source that is available for use by the research community.
  
  
  METHODS
  EnvIMS is a multinational case-control study, enrolling 2,800 cases with MS and 5,012 population-based controls in Canada, Italy, Norway, Serbia and Sweden. The study was designed to investigate the most commonly implicated risk factors for MS etiology using a self-report questionnaire.
  
  
  CONCLUSIONS
  The use of a common methodology to study MS etiology across several countries enhances the comparability of results in different geographic regions and research settings, reduces the resources required for study design and enhances the opportunity for data harmonization.
authors.affiliation: Research Institute of the McGill University Health Centre, Montreal, Que., Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Magalhaes
authors.forename: Maura
authors.initials: M
authors.lastname: Pugliatti
authors.forename: Ilaria
authors.initials: I
authors.lastname: Casetta
authors.forename: Jelena
authors.initials: J
authors.lastname: Drulovic
authors.forename: Enrico
authors.initials: E
authors.lastname: Granieri
authors.forename: Trygve
authors.initials: T
authors.lastname: Holmøy
authors.forename: Margitta T
authors.initials: MT
authors.lastname: Kampman
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Landtblom
authors.forename: Klaus
authors.initials: K
authors.lastname: Lauer
authors.forename: Kjell-Morten
authors.initials: KM
authors.lastname: Myhr
authors.forename: Maria
authors.initials: M
authors.lastname: Parpinel
authors.forename: Tatjana
authors.initials: T
authors.lastname: Pekmezovic
authors.forename: Trond
authors.initials: T
authors.lastname: Riise
authors.forename: David
authors.initials: D
authors.lastname: Wolfson
authors.forename: Bin
authors.initials: B
authors.lastname: Zhu
authors.forename: Christina
authors.initials: C
authors.lastname: Wolfson
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004777:Environment; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000209:etiology*; D012107:Research Design; D012307:Risk Factors; D057566:Self Report; D011795:Surveys and Questionnaires