title: Prevalence of multiple sclerosis in Iranian emigrants: review of the evidence.
abstract: Iran has the highest prevalence of multiple sclerosis (MS) in the Middle East and Asia. Rate of emigration has been significantly raised among Iranians and though, multiple studies have been published on prevalence of MS among Iranian emigrants. Here we systematically reviewed these publications. We performed a comprehensive literature search was performed on April 30, 2015 in data bases of MEDLINE, EMBASE, Scopus and Google Scholar for the terms 'multiple sclerosis', 'incidence', 'prevalence', 'epidemiology', 'migration', 'emigrant', 'immigrant', 'Iran', 'Parsis' and 'Persian'. Study location, prevalence day or period, and age of at disease onset were recorded for all the included publications. Nine publications from Sweden, Canada, Norway, UK, and India were included. Only three reported age-adjusted prevalence and six reported age of disease onset. MS prevalence among Iranian emigrants varied from 21 per 100,000 people in Bombay, India in 1985 to 433 per 100,000 people in British Columbia, Canada in 2012. Five studies reported the prevalence in the region of interest, ranging from 1.33 in Bombay, India to 240 in British Columbia, Canada. Five studies also reported the prevalence of MS in the population of the destination country, and in all of them, the prevalence of MS was higher in Iranian immigrants compared to native people. Prevalence studies performed in Iran and also on Iranian emigrants indicate roles for both genetic and environmental factors in MS susceptibility. Data might indicate that living in a high-risk area increases the susceptibility to MS.
authors.affiliation: Isfahan Research Committee of Multiple Sclerosis, Isfahan University of Medical Sciences, Isfahan, Iran. zahranasr1@yahoo.com.|Medical Students' Research Center, Isfahan University of Medical Sciences, Isfahan, Iran. zahranasr1@yahoo.com.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Nasr
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, MN, USA.|Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Masoud
authors.initials: M
authors.lastname: Majed
authors.affiliation: Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Abdolmohamad
authors.initials: A
authors.lastname: Rostami
authors.affiliation: Department of Neurology and MS Research Center, Neuroscience Institute, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohamad Ali
authors.initials: MA
authors.lastname: Sahraian
authors.affiliation: Department of Neurology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71130, USA.
authors.forename: Alireza
authors.initials: A
authors.lastname: Minagar
authors.affiliation: Department of Neuroscience, Physiology and Pharmacology, Faculty of Life Sciences, University College London, London, UK.
authors.forename: Arman
authors.initials: A
authors.lastname: Amini
authors.affiliation: Department of Neurology, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA, 71130, USA.
authors.forename: Jeanine C
authors.initials: JC
authors.lastname: McGee
authors.affiliation: Isfahan Research Committee of Multiple Sclerosis, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Etemadifar
mesh_terms: D001955:British Columbia / Q000208:ethnology; D054242:Emigrants and Immigrants / Q000706:statistics & numerical data*; D006801:Humans; D007194:India / Q000208:ethnology; D007492:Iran / Q000208:ethnology; D008131:London / Q000208:ethnology; D009103:Multiple Sclerosis / Q000208:ethnology*; D009664:Norway / Q000208:ethnology; D015995:Prevalence; D013548:Sweden / Q000208:ethnology
keywords: Epidemiology; Immigrant; Multiple sclerosis; Risk