25-Hydroxyvitamin D [25(OH)D] levels and diabetic foot ulcer: Is there any relationship?

Aims: In recent years, there has been an effort to understand possible roles of 25(OH) D, including its role in the immune system particularly on T cell medicated immunity, pancreatic insulin secretion and insulin action. 25(OH) D stimulates the cell differentiation and reduces cell proliferation, which is essential for cell growth and wound healing. However, data on the association between low level of plasma 25(OH) D and diabetic foot syndrome are scarce. Materials and Methods: Circulating plasma levels of 25(OH) D were measured in diabetic patients with ulcer (n = 162) and without ulcer (n = 162) in a prospective cohort hospital based study. Results: Of these patients, 85.1% had type 2 diabetes. Subjects with diabetic foot ulcer showed lower median plasma level of 25(OH) D [6.3(4.2-11.1) vs 28.0(21.4-37.0)] ng/ml after adjusting the age and BMI. Regardless of the low levels of 25(OH) D in cases and controls, it was associated with neuropathy, sex (female), duration of ulcer healing, and smoking status and independent of confounding factors, including BMI (kg/m(2)), A1c (%), hypertension, nephropathy, foot ulcer, retinopathy, CAD, PAD, HDL-C (mg/dl) and LDL-C (mg/dl). The factors which predict the risk of developing ulcer independent of 25(OH) D status were A1c (>6.9%) [OR 4.37; RR 1.77], HDL-C (<40 mg/dl) [OR 1.16; RR 1.07], LDL-C (>100 mg/dl) [OR 1.07; RR 1.03], triglycerides (>200 mg/dl) [OR 1.40; RR 1.19], neuropathy [OR 6.88; RR 3.12], retinopathy [OR 3.34; RR 1.91], hypertension [OR 1.64; RR 1.28], nephropathy [OR 3.12; RR 1.87] and smoking [OR 4.53; RR 2.99] using odds and risk ratios. Conclusion: It is not clear whether the suppression of delayed wound healing seen during 25(OH) D deficiency is due to the secondary effect or is a direct action of vitamin D on certain components of the immune system. Long-term randomized trials are needed to see the impact of vitamin D supplementation on the outcome of diabetic foot patients. (C) 2013 Diabetes India. Published by Elsevier Ltd. All rights reserved.