1. Institute of Social and Preventive Medicine University of Bern Bern Switzerland
2. Graduate School for Health Sciences University of Bern Bern Switzerland
3. Department of Paediatrics, Inselspital, Bern University Hospital, Division of Paediatric Respiratory Medicine University of Bern Bern Switzerland
4. Department of Respiratory Medicine, University Children's Hospital Zurich and Children's Research Centre University of Zurich Basel Switzerland
5. University Children's Hospital Basel UKBB Basel Switzerland
6. Division of Paediatric Pulmonology, Children's Hospital Cantonal Hospital Lucerne Lucerne Switzerland