[1] Univ Autonoma Barcelona, CIBEREHD, Inst Salud Carlos 3,Dept Med,Digest Dis Dept, Unitat Malalties Digest,Hosp Sabadell,Inst Univ P, Barcelona 08208, Spain
[2] Univ Autonoma Barcelona, Fundacio Parc Tauli, Unitat Epidemiol & Avaluacio, Barcelona 08208, Spain
[3] Ctr Invest Biomed Red Enfermedades Hepat & Digest, Inst Salud Carlos 3, Madrid, Spain
[4] Hosp Clin Barcelona, Inst Malalties Digest, Serv Gastroenterol, Barcelona, Spain
[5] Hosp Princesa, Inst Invest Sanitaria Princesa IP, Serv Aparato Digest, Madrid, Spain
[6] McGill Univ, McGill Univ Hlth Ctr, Div Gastroenterol, Montreal, PQ, Canada
[7] McGill Univ, Dept Clin Epidemiol, Montreal, PQ, Canada