1. Institute for Medical Informatics, Biometry, and Epidemiology, University Duisburg-Essen, Essen, Germany
2. Institute for Medical Biometry, Epidemiology, and Informatics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
3. Institute of Medical Sociology, Heinrich Heine University, Düsseldorf, Germany
4. West German Heart Center, University Hospital, University of Duisburg-Essen, Essen, Germany
5. Leibniz Research Institute for Environmental Medicine and Medical Faculty, University of Düsseldorf, Düsseldorf, Germany