1 Metabolic Research Laboratory, Department of Endocrinology & Nutrition, Clínica Universidad de Navarra, University of Navarra, IdiSNA, CIBEROBN, 31008 Pamplona, Spain.
2 Metabolic Research Laboratory, Department of Endocrinology & Nutrition, Clínica Universidad de Navarra, University of Navarra, IdiSNA, CIBEROBN, 31008 Pamplona, Spain. Electronic address: gfruhbeck@unav.es.