[1] Vestfold Hosp Trust, Norwegian Natl Ctr Ageing & Hlth, Tonsberg, Norway
[2] Univ Oslo, Inst Clin Med, Oslo, Norway
[3] Oslo Univ Hosp, Dept Geriatr Med, Oslo, Norway
[4] Molde Univ Coll, Fac Hlth Sci & Social Care, Molde, Norway
[5] Ageing & Hlth, Postboks 2136, N-3103 Tonsberg, Norway