Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 5 2013 05 15 289 292 EN Mehrdokht Mazdeh Department of Neurology, Hamadan University of Medical Sciences, Hamadan, Iran. Soroush Seifirad Endocrinology and Metabolism Research Center, Tehran University of Medical Sciences, Tehran, Iran. Niloofar Kazemi Medical Student, Hamadan University of Medical Sciences, Hamadan, Iran. Mohammad Ali Seifrabie Department of Social Medicine, Hamadan University of Medical Sciences, Hamadan, Iran. Arash Dehghan Department of Pathology, Hamadan University of Medical Sciences, Hamadan, Iran. Hamidreza Abbasi Medical Student, Hamadan University of Medical Sciences, Hamadan, Iran. 2015 10 11 Multiple risk factors are introduced for Multiple Sclerosis (MS). Recent studies have suggested a possible correlation between vitamin D deficiency and an increase risk of MS. This study was therefore undertaken to compare vitamin D levels in new cases of MS and their relatives as healthy controls. Seventy five new diagnosed MS patients and 100 matched healthy controls among their relatives were enrolled in this study. Two groups were matched for gender, age, season in which serum level of vitamin D was checked and region and diet. Serum levels of 25-hydroxy vitamin D was measured, recorded and analyzed. Seventy five patients (57 female and 18 male) and 100 healthy subjects (75 female and 25 male) were enrolled in this study. The mean serum levels of 25-hydroxy vitamin D in case and control groups were 11.31 and 17.9 ng/ml, respectively (P=0.003). Compared to the healthy subject, serum levels of vitamin D were significantly lower in patients with MS. This difference was only significant in women. Observed difference of vitamin D levels of both groups were significant in summer. This study continues to support the role of vitamin D deficiency in MS. https://acta.tums.ac.ir/index.php/acta/article/view/4445 https://acta.tums.ac.ir/index.php/acta/article/download/4445/4578