A Retrospective Analysis of the Relationship Between 25-OH-Vitamin D and Diabetic Foot Ulcer

BACKGROUND: The fat-soluble molecule vitamin D has attracted much attention since its pleiotropism was discovered. Its effectiveness can be attributed to the presence of vitamin D receptors in most of the body’s tissues. Based on the classical role of vitamin D in regulating calcium and phosphorus metabolism and maintaining bone health, the role of vitamin D in immunity, type 2 diabetes mellitus (T2DM), tumor and cardiovascular diseases has been further discovered. Some experiments have shown that vitamin D can restore the production of antimicrobial peptides (AMP) in primary diabetic foot ulcer (DFU) cells, which can improve in vitro wound healing, indicating its potential therapeutic use in DFU therapy. In addition, vitamin D can also inhibit the secretion of T-helper type 1 (Th1) cytokines IFN-Y and IL-2 while stimulating the production of Th2 cytokines, thereby promoting wound healing. OBJECTIVE: To investigate the relationship between 25-OH-vitamin D level and DFU in diabetes mellitus (DM) patients, and to provide a theoretical basis for the early prevention and treatment of DFU. METHODS: The clinical data of 429 hospitalized patients with DM were retrospectively analyzed in this case–control study. The patients were divided into the DFU group (n = 242) and non-DFU group (n = 187). Fasting venous blood was drawn from all subjects to detect serum 25-OH-vitamin D levels and blood biochemical parameters, the difference of parameters between DFU group and non-DFU group were analyzed, and the risk factors of DFU were analyzed by logistic regression. RESULTS: The difference between the two groups in age, DM duration, gender, diastolic blood pressure, serum creatinine, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, albumin, white blood cell count, hemoglobin, hematocrit, 25-OH-vitamin D was statistically significant (p < 0.05). Multivariate logistic regression analysis showed that 25-OH-vitamin D is an independent protective factor for DFU [OR 95%, CI 0.984 (0.969, 0.998), p < 0.05]. 25-OH-vitamin D nutrition status distribution was different between non-DFU group and DFU group (P < 0.05). Vitamin D deficiency (< 50 nmol/L) accounted for 86.78% of all DFU patients, which was only 74.33% in non-DFU patients. The 25-OH-vitamin D levels of DFU patients from Wagner Grades 1 to 5 showed a downward trend (p < 0.01). CONCLUSION: In conclusion, our study confirms that 25-OH-vitamin D is closely correlated with DFU and that 25-OH-vitamin D is an independent protective factor for DFU. Therefore, vitamin D screening or supplementation might be beneficial to prevent DFU and improve the prognosis of DM patients.