[1] Newcastle Univ, Populat Hlth Sci Inst, Natl Inst Hlth Res NIHR, Older People & Frailty Policy Res Unit, Newcastle Upon Tyne NE4 5PL, Tyne & Wear, England
[2] Univ Manchester, Older People & Frailty Policy Res Unit, Sch Hlth Sci, Natl Inst Hlth Res NIHR,Fac Biol Med & Hlth, Manchester M13 9PL, Lancs, England
[3] Univ Hong Kong, Fac Social Sci, Pokfulam Rd, Hong Kong, Peoples R China
[4] Univ Manchester, Fac Humanities, Sch Social Sci, Cathie Marsh Inst Social Res, Manchester, Lancs, England
[5] Univ Manchester, Fac Humanities, Sch Environm Educ & Dev, Sch Social Sci,Global Dev Inst, Manchester, Lancs, England
[6] London Sch Econ & Polit Sci, Care Policy & Evaluat Ctr, Natl Inst Hlth Res NIHR, Older People & Frailty Policy Res Unit, London WC2A 2AE, England