title: Risk factors of Multiple sclerosis and their Relation with Disease Severity: A Cross-sectional Study from Iran.
abstract: BACKGROUND
  Many risk factors have been investigated in multiple sclerosis (MS); however, few studies have focused on the association between risk factors and the disease severity. The aim of our study was to evaluate the association between some of these risk factors and MS severity in a population sample of Iranian patients.
  
  
  METHODS
  This cross-sectional study was conducted on 660 patients with MS. In addition to demographic variables, many potential risk factors were recorded. To compare the severity, progression index (PI) was calculated. This index is created by current Expanded Disability Status Scale (EDSS) /disease duration.
  
  
  RESULTS
  Univariate analysis revealed that active smoking status is related with MS severity. (P-value = 0.012). Furthermore, our findings demonstrated that age at the disease onset [P < 0.001; OR = 1.05 (95% CI: 1.03-1.07)], female gender [P = 0.002; OR = 1.86 (95% CI: 1.24-2.77)] and marital status [P = 0.002; OR = 1.71 (95% CI: 1.21-2.41)] correlated with the severity of MS in the adjusted model. MS severity was observed to be related with high school and academic studies ([P = 0.004; OR = 0.56 (95% CI: 0.38-0.83)], [P = 0.001; OR = 0.52 (95% CI: 0.35-0.78)]) (Primary/secondary school studies are used as reference). Moreover, there was an association between MS severity and occupation (white collar, pink collar) ([P = 0.006; OR = 0.32 (95% CI: 0.14-0.73)], [P = 0.007; OR = 0.47 (95% CI: 0.27-0.81)]) (Student is used as reference). Furthermore, the results showed a significant correlation between vision and motor symptoms as an initial symptom and PI (P = 0.001, P = 0.025).
  
  
  CONCLUSIONS
  Due to high cost of MS care and its moderate to severe disability, identification of factors influencing the MS severity is important. Our results demonstrated that the major modifiable factors related with MS severity in Iranian population, some protective and some promotive, were smoking, education, marital status and occupation. Prospective studies on larger scale are needed for further proof of these results.
authors.affiliation: 1)Immunoregulation Research Center, Shahed University, Tehran, Iran. 2)Medical Students Research Committee, Shahed University, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Abbasi
authors.affiliation: 3)Brain and Neuroscience Research Institute, Roayn, Tehran, Iran. 4)MS Research Unit, Mostafa Khomeini Hospital, Tehran, Iran.
authors.forename: Seyed Massood
authors.initials: SM
authors.lastname: Nabavi
authors.affiliation: Division of Clinical Geriatrics, Department of Neurobiology, Care Sciences, and Society (NVS), Karolinska Institutet; Stockholm, Sweden.
authors.forename: Seyed-Mohammad
authors.initials: SM
authors.lastname: Fereshtehnejad
authors.affiliation: Medical Students Research Committee, Shahed University, Tehran, Iran.
authors.forename: Iman
authors.initials: I
authors.lastname: Ansari
authors.affiliation: Medical Students Research Committee, Shahed University, Tehran, Iran.
authors.forename: Nikan
authors.initials: N
authors.lastname: Zerafatjou
authors.affiliation: Neurology Department, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Vahid
authors.initials: V
authors.lastname: Shayegannejad
authors.affiliation: Neurology Department, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
authors.forename: Seyed Ehsan
authors.initials: SE
authors.lastname: Mohammadianinejad
authors.affiliation: Neurology Department, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Farhoudi
authors.affiliation: Neurology Department, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Noorian
authors.affiliation: Neurology Department, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Nazanin
authors.initials: N
authors.lastname: Razazian
authors.affiliation: Neurology Department, Mazandaran University of Medical Sciences, Sari, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Abedini
authors.affiliation: Neurology Department, Arak University of Medical Sciences, Arak, Iran.
authors.forename: Fardin
authors.initials: F
authors.lastname: Faraji
mesh_terms: D000328:Adult; D017668:Age of Onset; D003430:Cross-Sectional Studies; D018450:Disease Progression; D004522:Educational Status; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D017533:Marital Status / Q000706:statistics & numerical data; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000503:physiopathology; D015999:Multivariate Analysis; D009790:Occupations / Q000706:statistics & numerical data; D016017:Odds Ratio; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D055815:Young Adult