Vitamin D deficiency is associated with disability and disease progression in multiple sclerosis patients independently of oxidative and nitrosative stress

The aim of this study was to assess vitamin D status in patients with multiple sclerosis (MS) and to evaluate whether it was associated with oxidative and nitrosative stress (O&NS) markers and disability. This study included 137 patients with MS and 218 healthy controls. The markers evaluated were serum levels of 25-hydroxyvitamin D, lipid hydroperoxides, advanced oxidation protein products (AOPP), nitric oxide metabolites (NOx), and total radical-trapping antioxidant parameter TRAP/UA. Patients with 25(OH)D < 20 ng/mL showed higher EDSS (p = 0.016), MSSS (p = 0.005) and lower AOPP (p = 0.046) than those with 25(OH)D 20 ng/mL. After the binary logistic regression analyses, EDSS and MSSS remained significantly associated with vitamin D deficiency. We showed that lower levels of 25(OH)D were associated with higher EDSS and MSSS independently of variables such as O&NS, age, sex, body mass index, ethnicity, MS therapy, use of interferon beta, and clinical forms of MS (odds ratio: 1380, 95% confidence interval 1.030-1.843, p = 0.031). Moreover, the study showed an association between serum levels of 25(OH)D and EDSS (r(2) = 0.115, p = 0.002), demonstrating that 25(OH)D may contribute with 11.5% of increase in EDSS. Our results suggest that vitamin D deficiency may be considered one of the predictors of the disability in MS patients, independently of their redox status and influence the progression of disability in MS. (C) 2017 Elsevier B.V. All rights reserved.