title: Multiple Sclerosis Associated Risk Factors: A Case-Control Study.
abstract: BACKGROUND
  Hamadan Province is one of the high-risk regions in Iran for Multiple sclerosis (MS). A majority of the epidemiological studies conducted in Iran addressing MS are descriptive. This study was conducted to assess MS and its associated risk factors in Hamadan Province, the west of Iran.
  
  
  METHODS
  This case-control study compared 100 patients with MS (case group) and 100 patients with acute infectious diseases (control group) from September 2013 to March 2014. A checklist was used to assess the demographic, medical, and family history of the patients. The Friedman-Rosenman questionnaire was also used to assess personality type. Statistical analysis was performed using logistic regression model with Stata 11 software program.
  
  
  RESULTS
  The adjusted odds ratio (OR) estimate of MS was 4.37 (95% CI: 2.33, 8.20) for females compared to males; 0.15 (95% CI: 0.06, 0.43) for people aged above 50 years compared to aged 14 to 29 years; 0.44 (95% CI: 0.21, 0.91) for overweight or obese people compared to normal weights. Crude OR indicated a significant association between the occurrence of MS and exclusive breast feeding, season of birth, and smoking. However, the association was not statistically significant after adjustment for other covariates.
  
  
  CONCLUSIONS
  The risk of MS is significantly lower in male gender, obese/overweight, and old people. Furthermore, non-smoking, non-exclusive breast-feeding, and born in autumn may increase the risk of MS but need further investigation. However, long-term large prospective cohort studies are needed to investigate the true effect of the potential risk factors on MS.
authors.affiliation: Modeling of Noncommunicable Diseases Research Center, Dept. of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Jalal
authors.initials: J
authors.lastname: Poorolajal
authors.affiliation: Dept. of Neurology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Mehrdokht
authors.initials: M
authors.lastname: Mazdeh
authors.affiliation: Dept. of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Saatchi
authors.affiliation: Dept. of Biostatistics, School of Paramedical Sciences, Student's Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Elaheh
authors.initials: E
authors.lastname: Talebi Ghane
authors.affiliation: Dept. of Social Medicine, School of Medicine, Qom University of Medical Sciences, Qom, Iran.
authors.forename: Azam
authors.initials: A
authors.lastname: Biderafsh
authors.affiliation: Dept. of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Bahar
authors.initials: B
authors.lastname: Lotfi
authors.affiliation: Dept. of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Feryadres
authors.affiliation: Dept. of Epidemiology & Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Khabat
authors.initials: K
authors.lastname: Pajohi
keywords: Case-control study; Iran; Multiple sclerosis; Risk factors