[1] Duke Univ, Sch Med, Dept Head & Neck Surg & Commun Sci, Durham, NC USA
[2] Duke Univ, Sch Med, Dept Populat Hlth Sci, Durham, NC USA
[3] Duke Clin Res Inst, Durham, NC USA
[4] Duke Univ, Sch Med, Dept Med, Div Geriatr, Durham, NC 27706 USA
[5] Duke Univ, Sch Med, Ctr Study Aging & Human Dev, Durham, NC 27706 USA
[6] Durham VA Med Ctr, Durham VA Geriatr Res Educ & Clin Ctr, Dept Med, Durham, NC USA