1. Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany
2. Department of Pneumology, Ruhrlandklinik, West German Lung Centre, University Hospital of Essen, University of Duisburg-Essen, Germany
3. Institute of Clinical Epidemiology, Medical Faculty, Martin-Luther-University of Halle-Wittenberg, Halle, Germany
4. Institute for Medical Sociology, University Clinic Düsseldorf, University of Düsseldorf, Düsseldorf, Germany
5. Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, University Duisburg-Essen, Essen, Germany
6. Clinic of Cardiology, Stiftung Krankenhaus Bethanien, Moers, Germany
7. Clinic of Cardiology, West German Heart Centre, University Hospital of Essen, University Duisburg-Essen, Essen, Germany