1. Institute of Public Health, Charité – Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
2. Institute for Medical Information Processing, Biometry and Epidemiology, LMU Munich, and Pettenkofer School of Public Health, Munich, Germany
3. MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
4. Department of Health Services Research and Policy, London School of Hygiene & Tropical Medicine, London, UK