1. Internal Medicine and Dermatology, Dietetics and, Cystic Fibrosis Centre Utrecht; University Medical Centre Utrecht; Utrecht The Netherlands
2. Department of Biostatistics; Julius Centre; University Medical Centre Utrecht; Utrecht The Netherlands
3. Department of Paediatric Pulmonology; Cystic Fibrosis Centre Utrecht; University Medical Centre Utrecht; Utrecht The Netherlands
4. Department of Paediatric Gastroenterology; Cystic Fibrosis Centre; University Medical Centre Utrecht; Utrecht The Netherlands