1. Medical Sociology, University of Regensburg, Dr.-Gessler-Straße 17, Regensburg 93051, Germany
2. Department of Health Services Research and Policy, Research School of Population Health, College of Health and Medicine, Australian National University, Australia
3. Social and Health Sciences in Sport, Institute of Sport Science, University of Bayreuth, Bavaria, Germany
4. Robert Koch Institute Deparment of Epidemiology and Health Monitoring, Berlin, Germany