1Department of Pediatrics, University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
2Department Internal Medicine, University Medical Center, 6500 HB Nijmegen, The Netherlands
3Wageningen Center for Food Sciences and Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, The Netherlands
4Division of Endocrinology, University Medical Center, 6500 HB Nijmegen, The Netherlands