title: The role of melatonin in the pathogenesis of multiple sclerosis: a case-control study.
abstract: BACKGROUND
  The association between the prevalence of multiple sclerosis (MS) and latitude gradient indicates the importance of environmental factors in MS susceptibility. Sunlight's ultraviolet radiation, its ability to influence melatonin, and an imbalance of melatonin in the central nervous system (CNS) may be involved in this process.
  
  
  METHODS
  This case-control study was conducted in Isfahan MS Society (IMSS), Isfahan, Iran. Enrollment was limited to patients with MS referring to the MS clinic of Alzahra and Kashani hospital during January and February 2012.
  
  
  RESULTS
  Thirty-five patients with MS and 35 healthy individuals were included in our study. The melatonin levels were analyzed using enzyme-linked immunosorbent assay (ELISA) kits. There was no significant difference between saliva melatonin level of two groups (patients and healthy individuals) (P = 0.417); however, after controlling the effect of age, a significant difference (P = 0.022) was found.
  
  
  CONCLUSIONS
  In the present study, it is proposed that environmental conditions in Isfahan city might have increased the susceptibility to MS, but more studies in different parts of the world are needed to evaluate this claim.
authors.affiliation: Department of Neurology, Isfahan Neurosciences Research Center, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Ghorbani
authors.forename: Mehri
authors.initials: M
authors.lastname: Salari
authors.forename: Vahid
authors.initials: V
authors.lastname: Shaygannejad
authors.forename: Rasul
authors.initials: R
authors.lastname: Norouzi
keywords: Environmental factors; melatonin; multiple sclerosis