[1] Western Univ, Schulich Sch Med & Dent, Dept Family Med, Ctr Studies Family Med, London, England
[2] Western Univ, Schulich Sch Med & Dent, Dept Epidemiol & Biostat, Ctr Studies Family Med, London, England
[3] Western Univ, Ctr Studies Family Med, London, England
[4] Western Univ, Dept Family Med, London, England
[5] Western Univ, Dept Epidemiol & Biostat, London, England
[6] Cent Site, Inst Clin Evaluat Sci, Toronto, ON, Canada