Does vitamin D affect diabetic neuropathic pain and balance?

Purpose: This randomized, placebo-controlled study examined the effect of vitamin D replacement therapy on neuropathic symptoms and balance in patients with diabetic neuropathic pain and low vitamin D levels. Patients and Methods: Among the 258 patients, the results in a total of 57 volunteers (32 in the treatment and 25 in the control arm) meeting the inclusion criteria are reported. Symptoms of neuropathic pain were assessed using Douleur Neuropathique 4 (DN4) questionnaire, and presence of polyneuropathy (PNP) was determined by performing electro-myography (EMG). Balance was assessed using Berg balance test (BBT). After undergoing these examinations, the patients in the treatment group were intramuscularly (IM) injected with 300,000 IU vitamin D in a liquid formulation and those in the placebo group were IM injected with physiological saline. The DN4 and BBT were repeated after 12 weeks, and the results were compared. Results: The patients in the treatment group showed a significant decrease in total DN4 scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.008). The patients in the treatment group also showed a significant increase in BBT scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.001). Furthermore, in subgroup analysis, these patients showed a significant decrease in electric shock and burning sensation scores from baseline to the study endpoint compared with the patients in the placebo group (p=0.006, p=0.001, respectively). Conclusion: In patients with diabetic neuropathic pain, vitamin D levels should be measured and vitamin D replacement therapy should be administered as required to resolve neuropathic symptoms and to improve balance.