2735-LB: Vitamin D Deficiency and Risk of Diabetic Foot Ulcer: A Meta-analysis

Introduction and Objective: Diabetic foot ulcer (DFU) is a severe complication of diabetes associated with high disability and amputation rates. We performed this meta-analysis to evaluate the relationship between vitamin D deficiency and the risk of diabetic foot ulcer. Methods: We systematically searched PubMed, Embase, and Web of Science up to December 2025 for observational studies comparing vitamin D status between DFU patients and Non-DFU group. Vitamin D deficiency (VDD) and vitamin D insufficiency (VDI) were defined as serum 25(OH)D level < 20 ng/mL and of 20-29.9 ng/mL, respectively. Data were pooled using random-effects models. Mean difference (MD) and odds ratio (OR) with 95% confidence intervals (CI) were calculated. Heterogeneity was assessed by I²statistic, and study quality was evaluated using the Newcastle-Ottawa Scale. Results: A total of 21 studies involving 9,570 participants were included. Pooled results showed that DFU patients had significantly lower serum 25(OH)D levels than non-DFU patients (MD = -5.77 ng/mL, 95% CI: -7.87 to -3.66, P < 0.001). Vitamin D deficiency was associated with an increased risk of DFU (OR = 1.82, 95% CI: 1.32-2.52, P < 0.001), and severe deficiency further elevated the risk (OR = 3.22, 95% CI: 2.42-4.28, P < 0.001). No significant publication bias was detected. Conclusion: Vitamin D insufficiency and deficiency are strongly associated with higher risk of diabetic foot ulcer. Large-scale prospective cohorts and randomized controlled trials are warranted to establish the causal relationship. Routine screening and appropriate vitamin D supplementation in high-risk patients may help reduce DFU incidence and improve prognosis. Disclosure J. Yao: None. Y. Ding: None. M. Wang: None. G. Guo: None. L. Zhang: None.