Vitamin D and infection risk in patients with short bowel syndrome and intestinal failure.

PURPOSE: Patients with short bowel syndrome (SBS) and intestinal failure (IF) are highly susceptible to micronutrient deficiencies and recurrent infections. Vitamin D plays an important role in immune modulation and has been linked to infection outcomes in other high-risk populations, yet its relevance in SBS/IF remains unclear. This study evaluated the effectiveness of vitamin D supplementation and the association between serum 25-hydroxyvitamin D [25(OH)D] levels and infection risk in SBS/IF patients.

METHOD: In this single-center retrospective cohort study, 23 SBS/IF patients (8 pediatric, 34.8%) followed between November 2022 and November 2025 were included. Baseline 25(OH)D levels showed universal insufficiency, with 78.3% classified as deficient (<20 ng/mL). Changes in 25(OH)D levels at 6-12 months were compared between patients with and without supplementation using ANCOVA. The association between serial 25(OH)D levels and recurrent infection events was analyzed using a time-dependent Cox model with person-mean centering.

RESULTS

Vitamin D supplementation resulted in significantly greater increases in serum 25(OH)D compared with non-supplementation (mean change +15.61 vs. -0.40 ng/mL; ANCOVA F = 18.33, p = 0.001). During follow-up, 26 infection events occurred. Higher within-individual 25(OH)D levels were associated with a reduced hazard of infection (HR 0.92 per 1 ng/mL increase; 95% CI 0.869-0.976; p = 0.005).

CONCLUSION

Vitamin D supplementation effectively improves vitamin D levels in SBS/IF patients. Higher 25(OH)D levels were associated with lower infection hazard, suggesting vitamin D status may represent a modifiable factor related to infection risk in this population.