title: Does low socioeconomic status in early life protect against multiple sclerosis? A multinational, case-control study.
abstract: OBJECTIVE
  The findings from existing research on the association between socioeconomic status (SES) and multiple sclerosis (MS) are inconsistent. Most previous studies are limited to one country and do not adequately adjust for other risk factors for the disease.
  
  
  METHODS
  The association between SES and MS was examined using data from the multinational Environmental Risk Factors in Multiple Sclerosis (EnvIMS) case-control study, comprising 2144 cases and 3859 controls from Norway, Canada and Italy. Multiple logistic regression was used to estimate the odds ratios and 95% confidence intervals for the association between early life SES, measured by parental educational level, and MS. Analyses were adjusted for age, sex, sunlight exposure, history of infectious mononucleosis, smoking, obesity and family size.
  
  
  RESULTS
  Relative to those whose parents had primary school education or below, the adjusted odds ratio (95% confidence interval) for MS amongst individuals with university-educated parents, and the P value for trend across education levels, were 1.45 (1.03-2.05) in Canada (P for trend 0.030), 1.09 (0.85-1.39) in Norway (P for trend 0.395) and 0.65 (0.39-1.07) in Italy (P for trend 0.158).
  
  
  CONCLUSIONS
  There is no consistent association between parental SES and MS risk in Norway, Canada and Italy, with a protective effect of low SES only found in Canada.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Goulden
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Riise
authors.affiliation: Department of Neurology, Norwegian Multiple Sclerosis Competence Centre, Haukeland University Hospital, Bergen, Norway.|The KG Jebsen Centre for MS Research, Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: K-M
authors.initials: KM
authors.lastname: Myhr
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.|Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pugliatti
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.|Department of Medicine, McGill University, Montreal, QC, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Wolfson
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D004522:Educational Status; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000209:etiology*; D009664:Norway / Q000453:epidemiology; D065840:Protective Factors; D012042:Registries / Q000706:statistics & numerical data*; D012923:Social Class
keywords: case-control; epidemiology; multiple sclerosis; risk factors; socioeconomic status