International Journal of Preventive Medicine (Int J Prev Med)2008-7802982018081919421942ENIsfahan Neuroscience Research Center, Department of Neurology, Alzahra Hospital, Isfahan University of Medical Sciences, IsfahanIsfahan Neuroscience Research Center, Department of Neurology, Alzahra Hospital & Food Security Research Center and Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan & Department of Nutrition, School of Public Health, Iran University of Medical Sciences, TehranFood Security Research Center and Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, IsfahanIsfahan Neuroscience Research Center, Department of Neurology, Alzahra Hospital & Student Research Committee, Isfahan University of Medical Sciences, IsfahanDepartment of Epidemiology and Biostatics, Isfahan University of Medical Sciences, IsfahanFood Security Research Center and Department of Community Nutrition, School of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan20180818<p><strong>Background</strong>: Neuromyelitis optica spectrum disorder (NMOSD) is a central nervous system inflammatory disorder in which immunoglobulin G (IgG) autoantibodies possibly play a pathogenic role against the aquaporin‑4 water channel protein. Vitamin D may modulate B‑cell function and decrease the IgG synthesis and may play a role in NMOSD as a crucial factor. The aim of this study was to investigate the relation between Vitamin D intakes from food, Vitamin D intake from sunlight exposure, blood Vitamin D levels, and IgG‑neuromyelitis optica (NMO) level in serum of patients with NMOSD and NMO.</p><p><strong>Method</strong>: In this cross-sectional study, food Frequency Questionnaires (FFQ) and Sun Exposure Questionnaire (SEQ) were completed to evaluate of vitamin D intakes from food and sun light exposure. Moreover, serum levels of 25(OH) vitamin D3 and IgG-NMO were assessed in patients with NMOSD and NMO.</p><p><strong>Results</strong>: We assessed IgG‑NMO levels in 29 patients with NMOSD that nine patients (n = 31%) were positive and for the rest it was negative. Sunlight exposure scale (P = 0.01) and 25(OH) D3 (P = 0.04) in IgG‑NMO‑negative patients were significantly more than patients with positive IgG‑NMO. Age, gender, and latitude were not confounder variables. A positive significant correlation was observed between the sun exposure scale and serum levels of 25(OH) D3 in all participants (r = 0.747, P &le; 0.001).</p><p><strong>Conclusions</strong>: Physiological variation in Vitamin D may apply a significant effect on IgG‑NMO synthesis in patients with NMO. Vitamin D may have significant role in pathogenesis of NMOSD and NMO.</p><p><strong>Keywords</strong>: Immunoglobulin G, neuromyelitis optica spectrum disorder, Vitamin D</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/1942http://ijpm.mui.ac.ir/index.php/ijpm/article/download/1942/717717767