[1] Mayo Clin, Dept Internal Med, Rochester, MN 55905 USA
[2] Univ Texas Med Branch Galveston, John Sealy Sch Med, Galveston, TX USA
[3] Univ Texas Med Branch, Div Cardiovasc Med, Galveston, TX USA
[4] Univ Texas Med Branch, Sch Publ & Populat Hlth, Dept Populat Hlth & Hlth Dispar, Galveston, TX USA
[5] Univ Texas Med Branch, Sealy Ctr Aging, Galveston, TX USA