[1] Univ British Columbia, Sch Populat & Publ Hlth, Vancouver, BC V6T 1Z3, Canada
[2] McMaster Univ, Fac Hlth Sci, Dept Clin Epidemiol & Biostat, Hamilton, ON, Canada
[3] Vancouver Isl Hlth Author, Victoria, BC, Canada
[4] Fraser Hlth, Burnaby, BC, Canada
[5] Prov Hlth Serv Author, Vancouver, BC, Canada
[6] Univ British Columbia, Dept Med, Vancouver, BC V6T 1Z3, Canada