[1] Univ British Columbia, Dept Pediat, 2D19-4480 Oak St, Vancouver, BC V6H 3V4, Canada
[2] Univ British Columbia, Sch Populat & Publ Hlth, 2206 East Mall, Vancouver, BC V6T 1Z3, Canada
[3] British Columbia Injury Res & Prevent Unit, F508-4480 Oak St, Vancouver, BC V6H 3V4, Canada
[4] British Columbia Childrens Hosp Res Inst, 950 West 28th Ave, Vancouver, BC V5Z 4H4, Canada
[5] Univ British Columbia, Sch Architecture & Landscape Architecture, 379-2357 Main Mall, Vancouver, BC V6T 1Z4, Canada