Acknowledgements.

Centre	Investigator	Contribution
Maastricht (project coordinotor), Department of Gastroenterology and Hepatology, University Hospital Maastricht, Maastricht, the Netherlands	Mia Cilissen	Collected data
	Marielle Romberg	Collected data
Almada, Departments of Gastroenterology and Pathology, Almada Regional Health Departments, Portugal	João Freitas	Collected data
	Paula Borrhalho Nunes	Collected data
Copenhagen, Department of Medical Gastroenterology, Herlev Hospital, University of Copenhagen, Herlev, Denmark	Vibeke Binder	Scientific advisor
	Ebbe Langholz	Scientific advisor
	Lene Riis	Collected data
Cremona, Servizio di Gastroenterologia, Ospedale di Cremona, Cremona, Italy	Patrizia Politi	Collected data
Dublin, Adelaide and Meath Hospital, Department of Gastroenterology, Trinity College, Tallaght, Dublin, Ireland	Asghar Qasim	Collected data
	Angie Harrington	Collected data
Firenze, UO di Gastroenterologia, Policlinico di Careggi, Firenze, Italy	Guiseppe d' Albasio	Scientific advisor
	Andrea Messori	Scientific advisor
Global Vitis, Wattstraat 52, Sassenheim, the Netherlands	Frederik Wessels	Developed data acquisition tools
	Ed van Hees
	Robert van Hees
Heerlen, Department of Pathology, Atrium Medisch Centrum Heerlen, the Netherlands	Marius Nap	Scientific advisor
Heraklion, Departments of Gastroenterology, University General Hospital, Heraklion, Crete, Greece	Athanasios G. Pallis	Collected data
	Ioannis G. Vlachonikolis
	Ioannis Koutroubakis
	Maria Tzardi
Ioannina, Division of Internal Medicine, University of Ioannina, Ioannina, Greece	Kostas Katsanos	Collected data
	Michel Economou	Collected data
Leuven, Department of Gastroenterology, UZ Gasthuisberg, Universiteit Leuven, Leuven, Belgium	Paul Rutgeerts	Scientific advisor
	Sofie Joossens	Collected data
	Greet Claessens	Collected data
Maastricht MEMIC, University of Maastricht, Maastricht, the Netherlands	Gilbert van Zeijl	Data manager
Milan, Universita degli Studi di Milano, Cattedra di Gastroenterologia, Milano, Italy	Tullio Ranzi	Scientific advisor
	Claudio Cortelezzi	Collected data
Oslo, Medical Department A, Rikshospitalet, University of Oslo, Oslo, Norway	Idar Lygren	Collected data
	Tomm Bernklev	Collected data
	Camilla Solberg	Collected data
	Ole Høie	Collected data
Department of Internal Medicine and Gastroenterology, Arcispedale S Maria Nuova, Reggio Emilia, Italy	Maria Grazia Mortilla	Collected data
	Marina Beltrami	Collected data
Torino, Divisione di Gastroenterologica, Largo Turati 62, Torin, Italy	Angelo Pera	Scientific advisor
Vigo, Hospital Xeral de Vigo, Vigo, Spain	Juan Clofent	Collected data
	Mercedes Butron	Collected data