[1] Univ Saskatchewan, Dept Community Hlth & Epidemiol, Saskatoon, SK S7N 5E5, Canada
[2] Univ Saskatchewan, Canadian Ctr Hlth & Safety Agr, Saskatoon, SK S7N 5E5, Canada
[3] Univ Saskatchewan, Dept Med, Saskatoon, SK S7N 5E5, Canada
[4] Univ Saskatchewan, Coll Nursing, Saskatoon, SK S7N 5E5, Canada
[5] Queens Univ, Dept Community Hlth & Epidemiol, Kingston, ON, Canada
[6] Queens Univ, Dept Emergency Med, Kingston, ON, Canada