[1] Univ N Carolina, Div Geriatr Med, Chapel Hill, NC USA
[2] Univ N Carolina, Ctr Aging & Hlth, Chapel Hill, NC USA
[3] Univ N Carolina, Univ North Carolina Hosp Chapel Hill, Chapel Hill, NC USA
[4] Univ North Carolina Chapel Hill, Gillings Sch Global Publ Hlth, Dept Nutr, Chapel Hill, NC USA
[5] Univ N Carolina, Cecil G Sheps Ctr Hlth Serv Res, Chapel Hill, NC USA
[6] 5003 Old Clin,CB 7550, Chapel Hill, NC 27599 USA