Copyright © 2016 Crohn's & Colitis Foundation of America, Inc.
Background: Vitamin D (25(OH)D) deficiency occurs in active Crohn's disease (CD) and may be secondary to reduced sunlight exposure and oral intake. Vitamin D-binding protein (VDBP) levels, however, fluctuate less with season and sunlight. The aim, therefore, was to examine patients with CD in remission and determine any associations between VDBP, serum 25(OH)D, and the calculated free 25(OH)D concentrations with the risk of disease flare. Methods: Subjects were identified from prospectively maintained inflammatory bowel disease databases at 3 teaching hospitals in Australia. Patients were in steroid-free clinical remission at the time of blood draw and were followed for at least 12 months. Total and epimer-25(OH)D 3, VDBP concentrations, and genotypes were determined. Results: A total of 309 patients with CD (46% men) met the inclusion criteria. A disease flare occurred in 100 (32.4%). Serum 25(OH)D 3 was deficient (