1. School of Health Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
2. Clinical Epidemiology Unit, Oncological Network Research and Prevention Institute-ISPRO, Firenze, Italy
3. University Clinic for Respiratory and Allergic Diseases Golnik, Golnik, Slovenia
4. Health Sciences School, Barber House Annex, The University of Sheffield, Sheffield, UK
5. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
6. Department of Public Health, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands