1. Institute of Social Medicine, Occupational Health and Public Health (ISAP), University of Leipzig, 04103 Leipzig, Germany
2. Health and Ageing Research Team (HART), School of Psychology, Massey University, Palmerston North 4474, New Zealand
3. Institute of General Practice and Family Medicine, Martin-Luther-University Halle-Wittenberg, 06112 Halle (Saale), Germany
4. Institute of General Practice, University of Kiel, 24105 Kiel, Germany
5. Institute of General Practice/Family Medicine, University Hospital of LMU Munich, 80336 Munich, Germany
6. Institute for General Practice, Work Group Medical Statistics and IT-Infrastructure, Hannover Medical School, 30625 Hannover, Germany
7. Department of Health Economics and Health Services Research, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
8. Institute for Community Medicine, University Medicine Greifswald, 17475 Greifswald, Germany
9. German Center for Neurodegenerative Diseases (DZNE), Site Rostock/Greifswald, 17489 Greifswald, Germany