[1] Schulich Sch Med & Dent, Epidemiol & Biostat, London, ON, Canada
[2] Univ Western Ontario, Epidemiol & Biostat, London, ON, Canada
[3] Western Univ, Robarts Res Inst, London, ON, Canada
[4] Univ Western Ontario, Geog & Environm, London, ON, Canada
[5] Schulich Sch Med & Dent, Anat & Cell Biol, London, ON, Canada
[6] Western Univ, Neurol, Dept Clin Neurol Sci, London, ON, Canada
[7] Schulich Sch Med & Dent, Pathol & Lab Med, London, ON, Canada