1. Department of Gastroenterology and Hepatology; University Hospital of Santa Maria; Medical School of Lisbon; Lisbon Portugal
2. ISCTE - Instituto Universitário de Lisboa; UNIDE - IUL; Lisbon Portugal
3. Epidemiology Division; Health Ministry of Portugal; Lisbon Portugal
4. Department of Gastroenterology and Hepatology; Hospital Beatriz Ângelo; Lisbon Portugal