[1] Univ Toronto, Temerty Fac Med, Toronto, ON, Canada
[2] Univ Ottawa, Dept Family Med, Ottawa, ON, Canada
[3] Univ Oxford, Med Sci Div, Oxford, England
[4] Western Univ, Dept Family Med, London, ON, Canada
[5] Univ Ottawa, Fac Med, Ottawa, ON, Canada
[6] Univ Oxford, Dept Psychiat, Oxford, England
[7] Univ Oxford, Nuffield Dept Orthopaed Rheumatol & Musculoskeleta, Oxford OX3 7LD, England
[8] Univ Warwick, Warwick Clin Trials Unit, Aylesbury, England
[9] Stoke Mandeville Hosp, Dept Plast Surg, Buckinghamshire Healthcare NHS Trust, Aylesbury, England