1. Department of Vascular Medicine, University of Groningen, University Medical Center, Groningen, The Netherlands
2. Department of Endocrinology, University of Groningen, University Medical Center, Groningen, The Netherlands
3. Department of Nephrology, University of Groningen, University Medical Center, Groningen, The Netherlands
4. Laboratory Corporation of America Holdings (LabCorp), Morrisville, NC, USA