1. Department of General Practice & Elderly Care Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
2. Groningen Research Institute for Asthma and COPD (GRIAC), Groningen, The Netherlands
3. General Practitioners Research Institute, Groningen, The Netherlands
4. Food Allergy Centre, Department of Woman and Child Health, Padua University Hospital, Padua, Italy
5. Department of Health Sciences, Unit of Global Health Economics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
6. Department of Clinical Pharmacy & Pharmacology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands