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.