1. Faculty of Human Sciences and Faculty of Medicine, Graduate School GROW – Gerontological Research on Well-being, University of Cologne, Albertus-Magnus-Platz , 50923 Cologne , Germany
2. Institute for Health Economics and Clinical Epidemiology, University Hospital Cologne , 50924 Cologne , Germany
3. Department of Operative Dentistry and Periodontology , Centre of Dental Medicine, , Cologne , Germany
4. University Hospital Cologne , Centre of Dental Medicine, , Cologne , Germany