Association of vitamin D deficiency with diabetic peripheral neuropathy and diabetic nephropathy in Tianjin, China

Background and Objectives: To evaluate the association of vitamin D deficiency with type 2 diabetic peripheral neuropathy (DPN) and diabetic nephropathy (DN). Methods and Study Design: A total of 287 type 2 diabetic patients were categorized in two ways, and each divided into two groups: DPN (n=164) and non-DPN (NDPN) groups (n=123); and DN (n=148) and non-DN (NDN) groups (n=139). Enzyme-linked immunosorbent assay was used to measure the 25-hydroxy vitamin D [25(OH)D-3] level. Correlation analysis between 25(OH)D-3 and other indicators was performed. Results: 25(OH)D-3 levels were lower in the DPN and DN groups than in the NDPN and NDN groups, and the difference was statistically significant (t=-6.23, -4.38, p<0.0001). Moreover, a higher proportion of patients in the DPN and DN groups exhibited vitamin D deficiency than those in the NDPN and NDN groups (chi(2)=22.231, 15.973, respectively, p<0.0001). Vitamin D was highly correlated with DPN, DN, diabetes duration, age, sex, fasting plasma glucose, blood urea nitrogen, total cholesterol, low density lipoprotein cholesterol, 24-h urinary microalbumin, and beta-2 microglobulin (r=-0.34 similar to -0.133, p<0.05). Binary logistic regression analysis revealed that vitamin D deficiency is an independent risk factor for DPN and DN (OR=3.53, 95% confidence interval [CI]: 2.06-6.03; OR=2.93, 95% CI: 1.71-5.03; respectively, p<0.0001). Conclusions: Vitamin D deficiency is closely correlated with DPN and DN and can be considered as an independent risk factor for DPN and DN.