ABSTRACT
BACKGROUND/AIMS: The exact relationship between vitamin D deficiency and inflammatory bowel disease (IBD) remains unclear. We evaluated the effect of vitamin D3 administration on inflammatory responses and disease severity in patients with IBD. METHODS: We investigated the serum 25-hydroxyvitamin D3 [25-(OH)D], C-reactive protein (CRP) levels and the partial Mayo score (PMS) in patients with IBD. Vitamin D3 was administered in patients with either vitamin D deficiency or insufficiency and CRP, serum vitamin D levels and PMS were re-examined at 6 months of administration. RESULTS: In 88 patients with Crohn's disease (CD), a negative correlation was found between serum vitamin D and CRP. In 178 patients with ulcerative colitis (UC), serum vitamin D showed no association with CRP or PMS. Serum vitamin D increased from 11.08±3.63 to 22.69±6.11 ng/mL in 29 patients with CD and from 11.45±4.10 to 24.20±6.61 ng/mL in 41 patients with UC who received vitamin D3 treatment (P<0.001 and P<0.001, respectively). In patients with CD, median ΔCRP was –0.24 in the normalized vitamin D group and –0.11 in the non-normalized group (P=0.308). In patients with UC, median ΔCRP was −0.01 in the normalized vitamin D group and 0.06 in the non-normalized group (P=0.359). CONCLUSIONS: Although a negative correlation was found between serum vitamin D and CRP levels in patients with CD, administration of vitamin D did not improve the CRP level in patients with CD. In patients with UC, serum vitamin D level was unrelated to CRP or PMS.