1. Department of Neurology, University Hospital Essen, Hufelandstr. 55, D-45122 Essen, Germany
2. Institute of Medical Informatics, Biometry and Epidemiology,
University of Duisburg-EssenEssen, Germany
3. Department of Cardiology, University Hospital Essen, Essen, Germany
4. Institute of Epidemiology and Social Medicine, University of Münster, Münster, Germany