1. Medical Department B, University Hospital of North Norway, Tromsø, Norway.
2. Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.
3. Institute of Community Medicine, University of Tromsø, Tromsø, Norway.
4. Department of Kidney Medicine, University Hospital of North Norway, Tromsø, Norway.
5. Medical Biochemistry, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
6. Department of Medical Biochemistry, University Hospital of North Norway, Tromsø, Norway.