1. Gastroenterology Department; Hospital Universitario Central de Asturias; Oviedo Spain
2. Instituto de Investigación Sanitaria del Principado de Asturias (ISPA); Oviedo Spain
3. Hematology Department; Hospital Universitario Central de Asturias; Oviedo Spain
4. Pathology Department; Hospital Universitario Central de Asturias; Oviedo Spain
5. Pediatrics Department; Hospital Universitario Central de Asturias; Oviedo Spain
6. Statistics Department; Universidad de Oviedo; Oviedo Spain