[1] McGill Univ, Dept Epidemiol Biostat & Occupat Hlth, Montreal, PQ, Canada
[2] McGill Univ, Dept Surg, Montreal, PQ, Canada
[3] Sir Mortimer B Davis Jewish Hosp, Colorectal Surg, Montreal, PQ, Canada
[4] McGill Univ, Res Inst, Ctr Hlth, Montreal, PQ, Canada
[5] McGill Univ, Div Clin Epidemiol, Dept Med, Montreal, PQ, Canada
[6] McGill Univ, Ctr Outcomes Res & Evaluat, Res Inst, Ctr Hlth, 5252 Maisonneuve Blvd W Off 3E-12, Montreal, PQ H4A 3S5, Canada