1. Department of General Practice, EMGO Institute, VU University Medical Centre, BT Amsterdam,
2. Department of General Practice, EMGO Institute, VU University Medical Centre, BT Amsterdam
3. Department of General Practice, Interdisciplinary Health Care and Geriatrics, Antwerp University, Campus Drie Eiken D.S528, Universiteitsplein ,1 Wilrijk
4. Department of Social Medicine, EMGO Institute, VU University Medical Centre, BT Amsterdam