[1] Univ Ottawa, Dept Med, Ottawa, ON, Canada
[2] Univ Ottawa, Dept Epidemiol & Community Med, Ottawa, ON, Canada
[3] Univ Calgary, Cumming Sch Med, Dept Med, Calgary, AB, Canada
[4] Ottawa Hosp, Res Inst, Dept Clin Epidemiol, Ottawa, ON, Canada
[5] Univ Calgary, Cumming Sch Med, Dept Community Hlth Sci, HSC G239,3330 Hosp Dr NW, Calgary, AB T2N 4N1, Canada