Investigating the relationship between vitamin D levels and immune-mediated colitis

Abstract

Background The aim of this study was to evaluate the potential association between serum vitamin D levels and the incidence and severity of immune-mediated colitis (IMC), and to explore the potential role of vitamin D supplementation as a preventative or therapeutic intervention.

Methods This was a single-center study in which we retrospectively reviewed patients who received immune checkpoint inhibitor (ICI) treatment, had serum vitamin D levels measured within 6 months before or after starting treatment, and subsequently developed IMC.

Results A total of 179 patients were included in the study. Patients were stratified by serum vitamin D levels: 121 (67.6%) had levels ≤40 ng/mL, and 58 (32.4%) had levels >40 ng/mL. Individuals with vitamin D levels ≤40 ng/mL had more severe diarrhea (65.0%) and severe colitis (48.0%), both defined as common terminology criteria for adverse events grade ≥2, compared to those with vitamin D levels >40 ng/mL (45.6% and 28.6%, respectively; P=0.022 and P=0.034). Univariate analysis revealed that patients receiving vitamin D during ICI therapy had ~1.9 times higher odds of requiring steroid treatment (odds ratio [OR] 1.899, 95% confidence interval [CI] 1.0338-3.474; P=0.038). Patients with grade ≥2 diarrhea had 11 times higher odds of requiring steroids (OR 11.11, 95%CI 5.35-22.73; P<0.001). Patients with colitis grade ≥2 had 3 times higher odds of steroid use (OR 3.08, 95%CI 1.54-6.13; P=0.001).

Conclusions This study suggests that there is a relationship between serum vitamin D levels and IMC. Vitamin D deficiency in those with IMC was associated with more severe disease, and those with more severe disease were more likely to require steroid therapy.

Keywords Immune checkpoint inhibitor, immune mediated colitis, vitamin D

Ann Gastroenterol 2026; 39 (3): 344-351