1 Institute of Medical Sociology, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany, dragano@med.uni-duesseldorf.de Institute of Medical Sociology, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany Clinicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland, Department of Epidemiology and Public Health, University College London, London, United Kingdom.