1. University Center of Geriatric Medicine, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
2. Knowledge Institute of the Dutch Association of Medical Specialists, 3502 GH Utrecht, The Netherlands
3. Department of Public Health, Erasmus University Medical Center, 3000 CA Rotterdam, The Netherlands
4. Department of Internal Medicine, Northwest Clinics, 1817 MS Alkmaar, The Netherlands
5. Department of Gerontology and Geriatrics, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands