1. Neurology Practice Leopoldstrasse, Munich
2. Institute for Community Medicine, University of Greifswald, Greifswald
3. Institute of Epidemiology and Social Medicine, University of Münster, Münster
4. Institute of Epidemiology, Helmholtz Centre Munich, Munich, German Research Centre for Environmental Health (GmbH), Neuherberg
5. Department of Neurology, University of Münster, Münster
6. Department of Neurology, Klinikum Grosshadern Ludwig-Maximilians-University Munich, Munich, Germany