The Vitamin D in Pediatric Crohn's Disease ( ViDiPeC-2 )

The purpose of this study is to determine if vitamin D as an adjuvant therapy can improve the outcome (i.e. fewer relapses) and the quality of life, including levels of physical activity, in children diagnosed Crohn's disease (CD).

Inclusion Criteria: 1. Age at randomization between 4 and 17 years inclusively 2. Pediatric Crohn's Disease Activity Index (PCDAI) ≤ 10 with no clinical symptoms (abdominal pain or blood in the stool) at inclusion 3. Receiving a stable dose for at least 4 weeks of any of the following drugs: Thiopurines, Methotrexate, or TNF-α inhibitors (Infliximab/Adalimumab) 4. Dosage of fecal calprotectin lower than 250 µg/g stool at inclusion. Exclusion Criteria: 1. History of surgery resulting in a permanent colostomy or ileostomy (because of the inability to calculate PCDAI at baseline) 2. Patients who have already been included in the pilots vitamin D trials 3. Patients actively enrolled in other CD drug trials.