1. Department of Respiratory Medicine Amsterdam University Medical Centres University of Amsterdam Amsterdam The Netherlands
2. Department of Paediatric Pulmonology Amsterdam University Medical Centres University of Amsterdam Amsterdam The Netherlands
3. Department of Clinical Pharmacy Haaglanden Medical Centre The Hague The Netherlands
4. Netherlands Twin Register Department of Biological Psychology Vrije Universiteit Amsterdam Amsterdam The Netherlands
5. Department of Paediatrics Division of Respiratory Medicine and Allergology ErasmusMC – Sophia Children’s Hospital University Medical Centre Rotterdam Rotterdam The Netherlands
6. Department of Paediatric Pulmonology & Paediatric Allergology University Medical Centre Groningen Beatrix Children’s Hospital University of Groningen Groningen The Netherlands
7. Groningen Research Institute for Asthma & COPD (GRIAC) University Medical Centre Groningen University of Groningen Groningen The Netherlands