[1] Dalarna Univ, Sch Hlth & Welf, S-79188 Falun, Sweden
[2] Univ Groningen, Urban & Reg Studies Inst, Fac Spatial Sci, Populat Res Ctr, POB 800, NL-9700 AV Groningen, Netherlands
[3] Univ Alberta, Dept Phys Therapy, Edmonton, AB T6G 2G4, Canada
[4] Karolinska Inst, Aging Res Ctr, S-17177 Stockholm, Sweden
[5] Stockholm Univ, S-17177 Stockholm, Sweden