1. Department of General Practice and Elderly Care Medicine, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
2. Amsterdam University of Applied Science, the Netherlands
3. Faculty of Medical Sciences, University Medical Centre Groningen, University of Groningen, Groningen, the Netherlands
4. Leyden Academy on Vitality and Ageing, Leiden, the Netherlands
5. Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, the Netherlands