[1] Univ Putra Malaysia, Fac Med & Hlth Sci, Dept Family Med, Serdang, Malaysia
[2] Univ Putra Malaysia, Fac Med & Hlth Sci, Malaysian Res Inst Ageing, Serdang, Malaysia
[3] Sunway Univ, Sch Healthcare & Med Sci, Dept Med Sci, Bandar Sunway, Malaysia
[4] Univ Cambridge, Sch Clin Med K TK & RL, Inst Publ Hlth, Dept Publ Hlth & Primary Care, Cambridge, England
[5] Univ Cambridge, MRC, Epidemiol Unit NW, Cambridge, England