Tehran University of Medical Sciences Current Journal of Neurology 2717-011X 12 2 2013 06 15 41 46 Hamidreza Hatamian Associate Professor, Department of Neurology, Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran. Elham Bidabadi Assistant Professor, Department of Pediatric Neurology, Guilan University of Medical Sciences, Rasht, Iran Seyed Mohammad Seyed Saadat Medical Student, Medical Student Research Committee, Guilan University of Medical Sciences, Rasht, Iran Niloufar Seyed Saadat Medical Student, Medical Student Research Committee, Guilan University of Medical Sciences, Rasht, Iran Ehsan Kazemnezhad Trauma Research Center, Guilan University of Medical Sciences, Rasht, Iran Hamed Ramezani Resident, Department of Neurology, Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran Babak Bakhshayesh Assistant Professor, Department of Neurology, Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran 2015 10 14 Background: Although the precise etiology of multiple sclerosis (MS) is unknown, it seems that both genetic and environmental factors are important. Recent studies suggest that low serum vitamin D levels are important environmental factor in MS. The aim of this study was to compare the serum levels of vitamin D between MS patients and healthy subjects, and to determine its association with disability in MS patients. Methods:  In this cross-sectional study, a total of 52 patients with MS were randomly recruited and matched for age and sex with 52 healthy subjects. Demographic characteristics and serum vitamin D levels for both groups, as well as duration of disease Expanded Disability Status Scale (EDSS) for MS patients were evaluated. Statistical analysis was performed by independent samples t-test and multiple linear regression analysis. Results: The mean serum vitamin D levels were 26.5 ± 16.3 ng/ml in MS patients vs. 37.1 ±19.7 in healthy subjects (P = 0.003). A linear regression analysis showed no significant association between vitamin D levels and EDSS score of patients with MS (P = 0.345), after adjusting for the covariates. Conclusion:Our findings did not suggest a protective association for serum vitamin D levels against disability in MS patients. https://ijnl.tums.ac.ir/index.php/ijnl/article/view/664 https://ijnl.tums.ac.ir/index.php/ijnl/article/download/664/138