Fig. 2

The correlations between serum 25(OH)VD levels and other clinical parameters in NDFO and DFO group (r). Pearson correlation analysis showed that serum 25(OH)VD levels were positively correlated with mean sunshine duration per day, ulcer time, Wagner grade, infection severity, recurrence of foot ulcer, HDL-C, P-IL-10, T-IL-10, and T-VDR levels in NDFO group and DFO group, (P < 0.05), but negatively correlation with season (winter), FPG, HbA1c, CRP, P-IL-6, and T-IL-6 levels (P < 0.05). Serum 25(OH)VD levels were also positively correlated with TcPO2 and ABI in the DFO group (P < 0.05), and negatively correlated with WBC, ESR (P < 0.05). NDFO diabetic foot ulcer without osteomyelitis, DFO diabetic foot osteomyelitis, DFU diabetic foot ulcer, SBP systolic blood pressure, DBP diastolic blood pressure, FPG fasting plasma glucose, HbA1c glycated hemoglobin A1c, TG triacylglycerol, TCH total cholesterol, LDL-Clow-density lipoprotein cholesterol, HDL-Chigh-density lipoprotein cholesterol, PTH parathyroid hormone, eGFR estimated glomerular filtration rate, ALB serum albumin, Hb haemoglobin, TcPO2 transcutaneous oxygen pressure, ABI ankle brachial index, CRP C-reactive protein, WBC white blood cell, ESR erythrocyte sedimentation rate, IL interleukin, T-IL-6 IL-6 mRNA expression in wound margin tissue, T-IL-10 IL-10 mRNA expression in wound margin tissue, T-VDR:Vitamin D receptor mRNA expression in wound margin tissue, IL interleukin, P-IL-6 IL-6 level in peripheral blood, P-IL-10 IL-10 level in peripheral blood.T-IL-6 IL-6 mRNA expression in wound margin tissue, T-IL-10 IL-10 mRNA expression in wound margin tissue,T-VDR vitamin D receptor mRNA expression in wound margin tissue