Low serum vitamin D levels in patients with myasthenia gravis.

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease. Vitamin D has important roles both in the autoimmune response and in skeletal muscles. We investigated the levels of 1,25-dihydroxy vitamin D [1,25(OH)2D] and 25-hydroxy vitamin D [25(OH)D] in patients with MG and healthy subjects. MG patients were classified by disease stage, age of onset and treatment status whether or not to taking immunosuppressive agents. MG patients had lower plasma 25(OH)D levels (mean, 18.8 ± 8.4 ng/mL) than healthy controls (26.3 ± 6.1 ng/mL) (p < .05). 1,25(OH)2D levels showed slightly high in MG patients than healthy controls, but had no significant difference between two groups. In addition, no significant differences were observed between two groups divided by clinical characteristics. Serum 25(OH)D levels significantly lower in patients with MG compared with healthy controls. We recommend monitoring of vitamin D status in patients with MG to avoid direct negative effects on the muscles or autoimmune response.