1. Division of Nephrology and Hypertension, Department of Medicine
2. Divisions of Nephrology
3. Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland
4. Department of Pediatrics, University of Kansas School of Medicine, Kansas City, USA
5. Endocrinology and Metabolism, Department of Medicine
6. Department of Clinical Biochemistry, Landspitali University Hospital, Reykjavik, Iceland