Prospective evaluation of the effect of short-term oral vitamin D supplementation on peripheral neuropathy in type 2 diabetes mellitus

ABSTRACT

We aimed to assess the efficacy of short-term oral vitamin D supplementation on peripheral neuropathy in patients with type 2 diabetes. Materials and This prospective, placebo-controlled trial included 112 type 2 diabetic patients with diabetic peripheral neuropathy [DPN] and vitamin D [25[OH]D] deficiency. Patients were sequentially assigned to a treatment group [n = 57] and a placebo group [n = 55]. DPN was assessed using a neuropathy symptom score [NSS], a neuropathy disability score [NDS] and a nerve conduction study [NCS]. Vitamin D status was determined by measuring the serum total 25[OH]D concentration. Patients received either oral vitamin D[3] capsules or starch capsules once weekly for 8 weeks. The primary outcome was changes in NSS and NDS from baseline. The secondary outcome was changes in the NCS result. Serum 25[OH]D concentrations significantly improved after oral vitamin D supplementation in the treatment group when compared to the placebo group [32.8 +/- 23.7 vs. 1.1 +/- 3.6, p < 0.0001]. Similarly, the improvement in NSS values was significantly greater in the treatment group than in the placebo group [-1.49 +/- 1.37 vs. -0.20 +/- 0.59, p < 0.001]. No improvement was observed for NDS and NCS between the 2 groups after treatment. Short-term oral vitamin D[3] supplementation improved vitamin D status and the symptoms of neuropathy in patients with type 2 diabetes