[1] Natl Taiwan Univ Hosp, Dept Internal Med, Taipei 100, Taiwan
[2] Natl Hlth Res Inst, Div Gerontol Res, Taipei, Taiwan
[3] Kaohsiung Med Univ, Kaohsiung, Taiwan
[4] Harvard Univ, Sch Med, Beth Israel Deaconess Med Ctr, Boston, MA USA
[5] Harvard Univ, Sch Med, Div Aging, Boston, MA USA