Vitamin D supplementation reduces infection rate and promotes wound healing in patients with diabetic foot ulcers

Table 3 The secondary outcomes: Wound healing, serum 25(OH)D levels, immune markers, and adverse events

Secondary outcome	VD group (n = 60)	Control group (n = 60)	P value
Wound healing
Baseline ulcer size (cm²)	5.6	5.4	-
Ulcer size at 6 weeks (cm²)	3.6 (35% reduction from baseline)	4.3 (20% reduction from baseline)	-
Ulcer size at 12 weeks (cm²)	2.2 (60% reduction from baseline)	3.5 (35% reduction from baseline)	< 0.01
Complete ulcer closure (%)	20%	10%	-
Serum 25(OH)D levels (ng/mL)
Baseline	16.5 ± 4.8	17.1 ± 5.0	0.47
Post-intervention (12 weeks)	35.2 ± 7.5	18.3 ± 5.2	< 0.001
Immune markers
Cathelicidin (change from baseline)	+30%	No significant change	< 0.01
Pro-inflammatory cytokines (IL-6, TNF-α)	-20%	No significant change	0.02
Adverse events
Hypercalcemia	0 cases	0 cases	-
Other side effects	None reported	None reported	-

Vitamin D (VD) supplementation correlated with notable enhancements in wound healing and serum 25(OH)D concentrations, along with an augmented immunological response, as shown by alterations in cathelicidin and pro-inflammatory cytokines. No adverse events were reported in either group, confirming the safety and tolerability of VD supplementation at 2000 IU/day. VD: Vitamin D; TNF-α: Tumor necrosis factor-α; IL: Interleukin.