[1] McGill Univ, Div Gastroenterol & Epidemiol, Montreal, PQ, Canada
[2] McGill Univ, Div Biostat, Montreal, PQ, Canada
[3] McGill Univ, Div Occupat Hlth, Montreal, PQ, Canada
[4] CHU Dijon, INSERM, CIC P 803, Dijon, France
[5] McGill Univ, Div Gastroenterol, Montreal, PQ, Canada
[6] Technion Israel Inst Technol, Dept Gastroenterol, Rappaport Fac Med, Haifa, Israel
[7] Chinese Univ Hong Kong, Dept Med & Therapeut, Prince Wales Hosp, Shatin, Hong Kong, Peoples R China