[1] Western Univ, Human Environm Anal Lab, London, ON N6A 3K7, Canada
[2] Western Univ, Dept Geog & Environm, London, ON N6A 5C2, Canada
[3] Childrens Hlth Res Inst, London, ON N6A 5A5, Canada
[4] Western Univ, Dept Epidemiol & Biostat, London, ON N6A 5C1, Canada
[5] Western Univ, Sch Hlth Studies, London, ON N6A 3K7, Canada
[6] Western Univ, Dept Paediat, London, ON N6A 3K7, Canada
[7] Lawson Hlth Res Inst, London, ON N6C 2R5, Canada