1. Faculty of Medicine and Health Technology, Tampere University; Allergy Centre, Tampere University Hospital, Tampere, Finland
2. Respiratory Medicine and Allergy, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
3. Department of Statistics, ZS Associates, Zurich, Switzerland
4. Department of Epidemiology, AstraZeneca, Mölndal, Sweden
5. Department of Statistics, ZS Associates, London, UK
6. Medical Department, AstraZeneca Nordic, Södertälje, Sweden