Relationship between peripheral neuropathy and vitamin D in elderly patients with type 2 diabetes

Abstract

Objective To investigate the levels of vitamin D and the correlation between DPN and vitamin D in elderly patients with diabetic peripheral neuropathy(DPN). Methods A total of 849 patients aged 60 years and over admitted into endocrinology department from June 2016 to September 2017 were enrolled in this retrospective case-control study.According to DPN diagnostic criteria, patients were divided into the non-DPN group(n=542)and the DPN group(n=307). The 25(OH)-vitamin D[25(OH)D]level and blood biochemical parameters were determined and compared between the two groups.The risk factors for DPN were analyzed using logistic regression analysis and plotting receiver operating characteristic(ROC)curves. Results The mean of serum 25(OH)D level in the 849 patients was 43.9±19.4 nmol/L.Serum 25(OH)D level was lower in the DPN patients than in the non-DPN patients[(40.9±20.4)nmol/L vs.(45.7±18.6)nmol/L, P<0.05]. The incidence of 25(OH)D deficiency was higher in the DPN group than in the non-DPN group(72.3% or 222/307 vs. 64.6% or 350/542, P<0.05). Binary logistic regression analysis indicated that 25(OH)D was a protective factor for DPN(OR=0.980, 95% CI: 0.964~0.995, P<0.05)and the disease duration was a risk factor for DPN(OR=1.048, 95% CI: 1.027~1.070, P<0.001). ROC analysis indicated that the diagnostic cut-off value of serum 25(OH)D for predicting DPN was 37.5nmol/L, with a Youden index of 0.17, sensitivity of 0.65 and specificity of 0.52. Conclusions The 25(OH)D level is much lower in diabetic patients, especially in DPN patients.Higher 25(OH)VD level might be a protective factor for DPN, and vitamin D might be one of potential biomarkers for DPN in diabetic patients. Key words: Diabetic neuropathies; Diabetes mellitus, type 2; Vitamin D