1. Pediatric Pulmonology and Sleep Medicine, Cystic Fibrosis Center, Children’s Hospital, University of Duisburg-Essen, 45147 Essen, Germany
2. Institute of Human Nutrition and Food Science, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
3. Department of Pulmonary Medicine, University Hospital Essen–Ruhrlandklinik, Adult Cystic Fibrosis Center, University of Duisburg-Essen, 45239 Essen, Germany
4. Department of Pediatric Pulmonology, University Children’s Hospital, Ruhr University Bochum, 44801 Bochum, Germany
5. Children’s Hospital, Marienhospital Wesel, 46483 Wesel, Germany