title: Risk factors for increased multiple sclerosis susceptibility in the Iranian population.
abstract: Multiple sclerosis (MS) is a complex autoimmune disease with increasing prevalence. Many factors have been assessed in relation to its development and its worldwide geographical and racial distribution. Therefore, we decided to conduct a nationwide case-control matched study to estimate the possible influence of putative risk factors on MS status in an Iranian MS population. Between January 2008 and September 2013, 1403 patients diagnosed with MS according to the Poser or McDonald criteria and 883 controls were studied. Of all patients, there were 921 women and 296 men (ratio 3.1:1) with a mean age of 32.6 ± 8.7 years. In the multivariate model adjusted for sex and age (±2years), we found associated risk factors of MS to be: history of any allergic condition (Odds ratio (OR): 1.92, 95% Confidence interval (CI): 1.55-2.47, p<0.001), and smoking (OR: 1.93, 95% CI: 1.31-2.73, p<0.001). Sunlight exposure ⩾ 3 hours was found to be associated with a reduced risk of MS (OR: 0.23, 95% CI: 0.15-0.31, p<0.001). As expected, cases were more likely to have a positive family history of MS than controls (OR: 1.91, 95% CI: 1.33-2.75, p<0.001). A significant association was found between family history of other autoimmune diseases and MS risk (OR: 1.57, 95% CI: 1.18-2.09, p=0.002). These results support the hypothesis that sun exposure is associated with a decreased risk of MS while smoking, autoimmune family history, MS family history, and personal allergy history are risk factors for MS susceptibility.
authors.affiliation: Department of Neurology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Behnam
authors.initials: B
authors.lastname: Mansouri
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Daneshju Boulevard, Evin, Tehran, Iran. Electronic address: asadollahi.shadi@yahoo.com.
authors.forename: Shadi
authors.initials: S
authors.lastname: Asadollahi
authors.affiliation: Department of Emergency Medicine, Shohadaye-Haftom Tir Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Kamran
authors.initials: K
authors.lastname: Heidari
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Daneshju Boulevard, Evin, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Fakhri
authors.affiliation: Department of Neurology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Farhad
authors.initials: F
authors.lastname: Assarzadegan
authors.affiliation: Department of Neurology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Nazari
authors.affiliation: Department of Neurology, School of Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Afshin
authors.initials: A
authors.lastname: Divani
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004198:Disease Susceptibility; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology; D007492:Iran; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology*; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D013472:Sunlight
keywords: Allergy; Autoimmune disease; Brain injury; Case-control; Iran; Multiple sclerosis; Risk factor