1. Basel Academy for Quality and Research in Medicine , Steinenring 6, Basel CH-4051, Switzerland
2. Department of Environmental Sciences, University of Basel , Spalenring 145, Basel CH-4055, Switzerland
3. Crossklinik , Bundesstrasse 1, Basel CH-4054, Switzerland
4. Faculty of Medicine, University of Basel , Klingelbergstrasse 61, Basel CH-4056, Switzerland
5. Department of Biostatistics, Bioinformatics and Biomathematics, Georgetown University , 4000 Reservoir Rd NW, Washington, DC 20057, USA
6. The Parker Institute, Copenhagen University Hospital , Bispebjerg and Frederiksberg, Nordre Fasanvej 57, Frederiksberg DK-2000, Denmark
7. Department of Clinical Epidemiology, Aarhus University , Olof Palmes Allé 43-45, Aarhus N DK-8200, Denmark