Vitamin D[3] concentration correlates with the severity of multiple sclerosis

To investigate the possible association between serum 25[OH] vitamin D[3] concentration and the severity of disease in Iranian patients with multiple sclerosis [MS] and to compare this concentration with a matched control group. This was an analytical cross sectional study performed at Jondishapour Neurology Clinic in Tehran, Iran. Patients with relapsing- remitting MS were categorized by disease severity: mild [0