Low Vitamin D Serum Levels in a Cohort of Myasthenia Gravis Patients in Argentina.

There are limited and controversial studies that address the role of vitamin D (vitD), a vitamin with immunomodulatory effects, in myasthenia gravis (MG), a neuromuscular autoimmune disease. We aimed to assess 25-hydroxy vitamin D (25(OH)D) levels and to evaluate possible associations with the clinical severity and other biomarkers of the disease. Serum levels of 25(OH)D, anti-acetylcholine receptor antibodies, and complement factor C5a were measured in MG patients (n=66) and healthy volunteers (HV) (n=25). Participants were evaluated through questionnaires to determine vitD intake and sunlight exposure. Severity scores were registered for MG patients. We found an 89.4% of MG individuals with non-sufficient levels of vitD, in comparison with 68.0% in the group of HV (OR=3.96; p=0.024). In addition, there was an inverse correlation between 25(OH)D levels and one of the scores (p=0.037 r=-0.26, CI95 =-0.49 to -0.0087). However, when we compared 25(OH)D median serum levels between MG patients and HV, no statistically significant differences have been found. This is the first report of vitD status in a cohort of Argentinean MG patients, where we found that patients are more likely to have non-sufficient levels of vitD compared to healthy people and that patients with more severe disease have lower levels of vitD.