[1] RFUCLMS, Dept Primary Care & Populat Sci, London NW3 2PF, England
[2] Univ Stirling, Ctr Social Res Dementia, Dept Appl Social Sci, Stirling, Scotland
[3] Univ Stirling, Dept Psychol, Stirling FK9 4LA, Scotland
[4] Univ Bradford, Bradford Dementia Grp, Sch Hlth Studies, Bradford, W Yorkshire, England
[5] Social Care Inst Excellence, London, England
[6] Univ Wales, Sch Nursing Midwifery & Hlth Studies, Fac Hlth Studies, Bangor, Gwynedd, Wales