1. Pediatric Surgery Department, Hospital Universitario de Navarra, Pamplona, Navarra, Spain
2. Department of Preventive Medicine and Public Health, University of Navarra, Pamplona, Navarra, Spain
3. Pathology Department, Hospital Universitario de Araba, Vitoria, Spain
4. Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Navarra, Spain
5. CIBER de Fisiopatología de la Obesidad y Nutrición, Instituto Salud Carlos III, Madrid, Spain