1. University of Ulm; Geriatric Research Unit, AGAPLESION Bethesda Hospital; Zollernring 26 Ulm Baden-Württemberg Germany 89073
2. University of Groningen, University Medical Center Groningen; Department of General Practice and Elderly Care Medicine; Groningen Netherlands
3. German Center for Neurodegenerative Diseases (DZNE); Witten North Rhine Westphalia Germany 58453
4. School of Public Health, Bielefeld University; Department of Health Services Research and Nursing Science; Universitätsstrasse 25 Bielefeld Germany 33615
5. University of Lübeck; Nursing Research Group, Institute of Social Medicine and Epidemiology; Ratzeburger Allee 160 Lübeck Germany D-23538