Association of Vitamin D with Inflammatory Bowel Disease Activity in Pediatric Patients

Background: It has been known that vitamin D level (serum 25[OH]D) has correlation with inflammatory bowel disease (IBD). The purpose of this study is to investigate changes of serum 25[OH]D in pediatric IBD patients according to the disease activity. Methods: A total of 96 children and adolescent with IBD were enrolled in this retrospective study. Serologic inflammatory markers and clinical disease activity scores of the patients were collected, and their correlations with serum 25[OH]D were analyzed. Seasonal variations of serum 25[OH]D were also investigated both in active disease state and remission state. Results: Of the 96 patients, 41 (43%) were women and patients with a vitamin D deficiency (< 20 ng/mL) at diagnosis were 77 (80.2%). There was no significant difference between Crohn's disease and ulcerative colitis for serum 25[OH]D. Serum 25[OH]D was higher in remission group than in active disease group (12.4 [8.8-29) ng/mL vs. 17.9 [12.3-34.4] ng/mL; P< 0.001) and the difference was more significant than other micronutrients. There was no significant difference in serum 25[OH]D concentration between patients with ileal involvement and patients without ileal involvement. There were seasonal variations in the active phase, but there was no significant difference by season in the remission phase. Conclusion: Serum 25[OH]D is inversely correlated with disease activity in IBD. Monitoring and supplementation is required especially for active disease status and in winter and spring season.