Pilot Study Evaluating Efficacy of 2 Regimens for Hypovitaminosis D Repletion in Pediatric Inflammatory Bowel Disease

Vitamin D is critical for skeletal health; hypovitaminosis D is common in pediatric inflammatory bowel disease (IBD), yet optimal repletion therapy is not well studied. We aimed to conduct a pilot trial comparing the efficacy of 2 vitamin D regimens of weekly dosing for the repletion of hypovitaminosis D in pediatric IBD.

Subjects identified from our IBD clinic with 25-hydroxyvitamin D (25[OH]D) concentrations <30 ng/mL were randomized to 10,000 (n = 18) or 5000 (n = 14) IU of oral vitamin D3/10 kg body weight per week for 6 weeks. Serum 25(OH)D, Ca, and parathyroid hormone concentrations were measured at baseline, week 8, and week 12.

In the higher dosing group, serum 25(OH)D increased from 23.7 ± 8.5 ng/mL at baseline to 49.2 ± 13.6 ng/mL at 8 weeks; P < 0.001. In the lower dosing group, serum 25(OH)D increased from 24.0 ± 7.0 ng/mL at baseline to 41.5 ± 9.6 ng/mL at 8 weeks; P < 0.001. At 12 weeks, serum 25(OH)D concentrations were 35.1 ± 8.4 and 30.8 ± 4.2 ng/mL for the higher and lower dose regimens, respectively. Mean serum Ca and parathyroid hormone concentrations did not significantly change during the study. No patient exhibited hypercalcemia, and no serious adverse events occurred.

Both treatment arms were safe and effective at normalizing vitamin D nutriture in pediatric IBD. Although significant repletion of 25(OH)D concentration was achieved in both dosing groups at 8 weeks, this effect was lost by the 12-week follow-up. Maintenance vitamin D therapy following initial repletion is likely required to maintain long-term normalized vitamin D status.