1. Department of Internal Medicine, Division of Nephrology, University of Groningen, University Medical Center Groningen, RB Groningen, the Netherlands
2. Division of Human Nutrition and Health, Wageningen University, HB Wageningen, the Netherlands
3. Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, RB Groningen, the Netherlands
4. Department of Internal Medicine, Division of Nephrology & Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, CA Rotterdam, The Netherlands
5. Department of Internal Medicine, Leiden University Medical Center, RC Leiden, the Netherlands
6. Department of Internal Medicine, Section of Nephrology, Amsterdam Cardiovascular Sciences, Amsterdam University Medical Centers, University of Amsterdam, DD Amsterdam Zuidoost, the Netherlands