[1] Newton Wellesley Hosp, Dept Surg, Div Gen & Gastrointestinal Surg, Sect Colon & Rectal Surg, Newton, MA 02462 USA
[2] Massachusetts Gen Hosp, Dept Surg, Div Gen & Gastrointestinal Surg, Sect Colon & Rectal Surg, Boston, MA 02114 USA
[3] Beth Israel Deaconess Med Ctr, Dept Med, Div Gerontol, Boston, MA 02215 USA
[4] Marcus Inst Aging Res, Hebrew Sr Life, Roslindale, MA 02131 USA
[5] Massachusetts Gen Hosp, Div Gen & Gastrointestinal Surg, 15 Parkman St,WAC 4-460, Boston, MA 02114 USA