1. Department of Internal Medicine, Diakonhjemmet Hospital, N-0370 Oslo, Norway
2. Institute of Clinical Medicine, University of Oslo, N-0316 Oslo, Norway
3. Department of Internal Medicine, Bærum Hospital, Vestre Viken Hospital Trust, N-1346 Gjettum, Norway
4. Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, N-1346 Gjettum, Norway