25-Hydroxyvitamin D Concentrations in Children with Crohn's Disease Supplemented with Either 2000 or 400 IU Daily for 6 Months: A Randomized Controlled Study

OBJECTIVES: To assess vitamin D status of pediatric patients with Crohn's disease (CD) and to compare their serum 25-hydroxyvitamin D (s-25OHD) with established cutoffs and assess whether 6 months of supplementation with 2000 IU/d, vs 400 IU/d, would reduce the group prevalence of vitamin D below these cutoffs. STUDY DESIGN: Subjects 8-18 years (n = 83) with quiescent CD were randomized to either 400 or 2000 IU vitamin D3/d for 6 months. RESULTS: Baseline mean ± SD s-25OHD was 24 ± 8 ng/mL; 13 subjects (16%) had an s-25OHD <16 ng/mL, 27 (33%) < 20 ng/mL, and 65 (79%) < 30 ng/mL. There was no significant difference between groups in achieving the cutoffs of 16 ng/mL or 20 ng/mL at 6 months; however, only 35% of the 400 IU group achieved the greater cutoff of 30 ng/mL compared with 74% in the 2000 IU group (P < .001). Baseline adjusted mean s-25OHD concentrations at 6 months were 9.6 ng/mL (95% CI 6.0-13.2, P < .001) greater in the 2000 IU than the 400 IU group. Disease activity was not affected by supplement dose. Few subjects exceeded safety marker cutoffs, and this did not differ by dose. CONCLUSIONS: At baseline, a high proportion of patients had a mean s-25OHD >20 ng/mL. 2000 IU vitamin D3/d is more effective in raising s-25OHD concentrations to > 30 ng/mL in children with CD than 400 IU/d, but both treatments were equally effective at achieving 16 or 20 ng/mL.