1. The Norwegian National Center for Aging and Health, Vestfold Hospital Trust, Tønsberg, Norway
2. Department of Geriatric Medicine, Oslo University Hospital, Oslo, Norway
3. Institute of Clinical Medicine, University of Oslo, Norway
4. Health Service Research Unit, Akershus University Hospital, Lørenskog, Norway
5. Levanger Hospital, Nord-Trøndelag Hospital Trust, Levanger, Norway
6. Institute of Clinical Medicine, Oslo University Hospital, Oslo, Norway