[1] Penn State Univ, Coll Med, Dept Surg, 500 Univ Dr,H137, Hershey, PA 17033 USA
[2] Penn State Univ, Coll Med, Div Colon & Rectal Surg, Hershey, PA 17033 USA
[3] Penn State Univ, Coll Med, Ctr Inflammatory Bowel Dis, Dept Surg,Div Gastroenterol, Hershey, PA 17033 USA
[4] Penn State Univ, Coll Med, Dept Publ Hlth Sci, Hershey, PA 17033 USA