title: Multiple sclerosis in the Iranian immigrant population of BC, Canada: prevalence and risk factors.
abstract: There is a well-documented increase in the risk of multiple sclerosis (MS) when migrating from a region of low prevalence to one of high prevalence.
  
  
  
  We present here an investigation of MS prevalence and candidate environmental and genetic risk factors among Iranian immigrants to British Columbia (BC), Canada.
  
  
  
  MS cases of Iranian ancestry were ascertained from a population-based Canadian study. We collected blood samples for genetic and serological analyses, and administered a personal history questionnaire to the cases.
  
  
  
  The crude prevalence of MS in this population of Iranian ancestry was 287/100,000 (95% CI: 229 - 356/100,000). MS cases were more likely to have a history of infectious mononucleosis (odds ratio (OR) = 7.5; p = 0.005) and smoking (OR = 17.0; p < 0.0001), as compared to healthy controls from previous studies in Iran. Cases were also more likely than controls to have been born between April and September (OR = 2.1; p = 0.019).
  
  
  
  The prevalence of MS among Iranian immigrants to Canada is greater than the overall prevalence of MS in Iran by a factor of at least four, and is similar to that recently observed among Iranian immigrants in other western nations. No major genetic susceptibility variants were identified, suggesting the environment in Canada may be what is increasing the risk of MS in this population.
authors.affiliation: Department of Medical Genetics, University of British Columbia (BC), Vancouver, Canada.
authors.forename: Colleen
authors.initials: C
authors.lastname: Guimond
authors.affiliation: Department of Medical Genetics, University of British Columbia (BC), Vancouver, Canada.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Lee
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, UK Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
authors.forename: Sreeram V
authors.initials: SV
authors.lastname: Ramagopalan
authors.affiliation: Department of Medical Genetics, University of Ottawa, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Dyment
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Canada Neurosciences and Mental Health Research Institute, The Hospital for Sick Children, University of Toronto, Canada.
authors.forename: Heather
authors.initials: H
authors.lastname: Hanwell
authors.affiliation: Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
authors.forename: Gavin
authors.initials: G
authors.lastname: Giovannoni
authors.affiliation: Department of Medical Genetics, University of British Columbia (BC), Vancouver, Canada.
authors.forename: Maria
authors.initials: M
authors.lastname: Criscuoli
authors.affiliation: Department of Medical Genetics, University of British Columbia (BC), Vancouver, Canada.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Yee
authors.affiliation: Department of Neurology, Fraser Health Multiple Sclerosis Clinic, Burnaby, Canada.
authors.forename: Galina
authors.initials: G
authors.lastname: Vorobeychik
authors.affiliation: Wellcome Trust Centre for Human Genetics, University of Oxford, UK Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
authors.forename: George C
authors.initials: GC
authors.lastname: Ebers
authors.affiliation: Department of Medical Genetics, University of British Columbia (BC), Vancouver, Canada Division of Neurology, University of BC, Vancouver, Canada sadovnik@infinet.net.
authors.forename: A Dessa
authors.initials: AD
authors.lastname: Sadovnick
mesh_terms: D000328:Adult; D017668:Age of Onset; D015415:Biomarkers / Q000097:blood; D001955:British Columbia / Q000453:epidemiology; D016022:Case-Control Studies; D054242:Emigrants and Immigrants; D004641:Emigration and Immigration; D005260:Female; D005787:Gene Frequency; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D059811:HLA-DRB1 Chains / Q000235:genetics; D006801:Humans; D007492:Iran / Q000208:ethnology; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology / Q000235:genetics; D016017:Odds Ratio; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D059811:HLA-DRB1 Chains
keywords: Canada; Iranian; cohort studies; environment; epidemiology; genetics; multiple sclerosis; prevalence; risk factors