[1] George Inst Int Hlth, Musculoskeletal Div, Sydney, NSW 2050, Australia
[2] Univ Sydney, Sch Publ Hlth, Sydney, NSW 2006, Australia
[3] Univ New S Wales, Falls & Balance Res Grp, Prince Wales Med Res Inst, Sydney, NSW, Australia
[4] Kings Coll Hosp London, Clin Age Res Unit, London, England
[5] Prince Wales Hosp, Dept Geriatr Med, Sydney, NSW, Australia