[1] Leiden Univ, Med Ctr, Dept Publ Hlth & Primary Care, Hippocratespad 2,Postbus 9600, NL-2300 RC Leiden, Netherlands
[2] Univ Nottingham, Div Med Sci & Grad Entry Med, Nottingham, England
[3] Royal Derby Hosp, Derby Med Sch, Room 4113, Derby DE22 3NE, England
[4] Maastricht Univ, Dept Family Med, Caphri Care & Publ Hlth Res Inst, Duboisdomein 30, NL-6229 GT Maastricht, Netherlands
[5] POB 616, NL-6200 MD Maastricht, Netherlands
[6] Leiden Univ, Med Ctr, Sect Gerontol & Geriatr, Dept Internal Med, Leiden, Netherlands
[7] Leiden Univ, Med Ctr, Dept Publ Hlth & Primary Care, Hippocratespad 21 Postzone,V0-P,Room V6-76, NL-2300 RC Leiden, Netherlands