title: Multiple sclerosis and immunological-related risk factors: results from a case-control study.
abstract: OBJECTIVE
  Multiple sclerosis is a demyeliting autoimmune inflammatory disorder of central nervous system (CNS) with unknown etiology, which afflicts more than 2.5 millions of the world's population. The aim of this study was to investigate the association between some immunological-related risk factors (tonsillectomy, appendectomy and hepatitis B vaccination) and multiple sclerosis in 2014 in Hamadan city, west of Iran.
  
  
  METHODS
  As a case-control study, data of filled questionnaire with written consents from 250 patients and 250 age and sex matched controls, were collected and analyzed using SPSS version 16 software and Logistic regression test.
  
  
  RESULTS
  In both groups, the case and the control, with average age of 33 years, 70% of the participants were women. Statistical analysis showed that there was no significant association between tonsillectomy and appendectomy with the multiple sclerosis (p > 0.05). Also hepatitis B vaccination did not increase the risk of MS significantly (p > 0.05), although there was a trend toward more vaccination rate in the patients.
  
  
  CONCLUSIONS
  Considering previous global investigations on this topic with the result of our study, it seems more studies are needed to determine the definitive association between tonsillectomy, appendectomy and hepatitis B vaccination with multiple sclerosis.
authors: Faculty of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Mohammad Mahdi
authors: MM
authors: Eftekharian
authors: Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Mehrnoush
authors: M
authors: Mousavi
authors: Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Mona Bahmani
authors: MB
authors: Hormoz
authors: Modeling of Noncommunicable diseases Research Center, Department of Biostatistics and Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Ghodratollah
authors: G
authors: Roshanaei
authors: Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
authors: Mehrdokht
authors: M
authors: Mazdeh
mesh_terms: D000328:Adult; D001062:Appendectomy / Q000009:adverse effects; D016022:Case-Control Studies; D005260:Female; D006509:Hepatitis B / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D006801:Humans; D007492:Iran; D016015:Logistic Models; D008297:Male; D009103:Multiple Sclerosis / Q000209:etiology / Q000276:immunology* / Q000473:pathology; D016017:Odds Ratio; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014068:Tonsillectomy / Q000009:adverse effects; D014611:Vaccination / Q000009:adverse effects*
keywords: Multiple sclerosis; appendectomy; hepatitis B vaccine; risk factors; tonsillectomy