摘要：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.
