1. West-German Heart Center Essen, University Duisburg-Essen, Germany
2. Institute of Medical Informatics, Biometry, and Epidemiology, University Duisburg-Essen, Germany
3. Institute for Medical Sociology, University of Düsseldorf, Germany
4. IUF-Leibniz Research Institute for Environmental Medicine, Germany; University of Düsseldorf, Germany
5. Cardioangiological Center Bethanien, Germany
6. Institute of Clinical Epidemiology, University Halle-Wittenberg, Halle, Germany