Vitamin D deficiency is associated with disease activity in patients with Crohn's disease

Background/Aims: Previous data suggest that vitamin D has a significant role in inflammatory bowel disease (IBD). We investigated the incidence of vitamin D deficiency in Korean patients with IBD and the correlation between serum vitamin D level and disease activity. Methods: We retrospectively analyzed the medical records of patients with IBD whose serum vitamin D levels were checked. Deficiency of 25-hydroxyvitamin D was defined as <20 ng/mL. Disease activity was evaluated using the partial Mayo score for ulcerative colitis (>= 2 defined as active disease) and Harvey-Bradshaw index for Crohn's disease (= 4 defined as active disease). Results: We enrolled 87 patients with IBD (ulcerative colitis [ UC], 45; Crohn's disease [ CD], 42). Among them, 65.5% (57/87) were men, with a mean age of 44.9 +/- 15.1 years (range, 18-75 years). The mean duration of disease was 4.7 +/- 4.8 years (range, 0.1-17.1 years). Vitamin D deficiency was found in 73.6% (64/87) of patients with IBD. Patients with IBD (mean vitamin D level, 16.3 +/- 9.0 ng/mL) showed lower vitamin D level than the healthy control group (mean vitamin D level, 20.4 +/- 7.0 ng/mL), with no statistically significant difference (P=0.136). Disease activity was inversely correlated with vitamin D deficiency in patients with CD (P=0.007). However, no correlation was observed in patients with UC (P=0.134). Conclusions: Approximately 75% of Korean patients with IBD showed vitamin D deficiency state. Vitamin D deficiency is associated with disease activity, particularly in patients with CD.