1 Public Health Unit, Institute of Health Sciences, Catholic University of Portugal, Lisbon, Portugal. henrique.lopes@ucp.pt.
2 Faculty of Health, Medicine and Life Sciences, Maastricht University, Institute of Health Sciences, Catholic University of Portugal, Lisbon, Portugal. ricardo.baptistaleite@gmail.com.
3 Public Health Unit, Institute of Health Sciences, Catholic University of Portugal, Lisbon, Portugal. diogofrancosharen@gmail.com.
4 Biostatistics and Medical Informatics, Department of Occupational Medicine. Faculty of Public Health, Medical University, Sofia. Bulgaria. tgk_70@abv.bg.
5 Clinic of Gastroenterology, St. Ivan Rilski University Hospital, Chair of Internal Medicine, Faculty of Medicine, Medical University, Sofia. Bulgaria. lucymateva@yahoo.com.
6 Clinic of Gastroenterology, St. Ivan Rilski University Hospital, Chair of Internal Medicine, Faculty of Medicine, Medical University, Sofia. Bulgaria. detjelev@gmail.com.
7 Clinic of Gastroenterology, Department of Gastroenterology, HPB Surgery and Transplantology, Military Medical Academy, Sofia, Bulgaria. simonova_m@yahoo.co.uk.