1. Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
2. University of Basel, Basel, Switzerland
3. Centre for Research in Environmental Epidemiology, Barcelona, Spain
4. Municipal Institute of Medical Research–Hospital del Mar, Barcelona, Spain
5. Universitat Pompeu Fabra, Barcelona, Spain
6. Centro de Investigación Biomédica en Red (CIBER) Epidemiologia y Salud Pública, Barcelona, Spain
7. Department of Community Medicine and Primary Care, University Hospitals, Geneva, Switzerland
8. Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
9. Ospedale Regionale di Lugano, Lugano, Switzerland
10. Division of Pulmonary Medicine, University Hospitals, Geneva, Switzerland