1. Department of Internal Medicine, Ziekenhuis Amstelveen, P.O. Box 328, 1180 AH Amstelveen, The Netherlands
2. Institute for Cardiovascular Research, Department of Internal Medicine, University Hospital Vrije Universiteit, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands
3. Department of Nutrition, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80152, 3508 TD Utrecht, The Netherlands
4. Research Institute for Endocrinology, Reproduction and Metabolism, Department of Endocrinology, University Hospital Vrije Universiteit, P.O. Box 7057, 1007 MB Amsterdam, The Netherlands