1 From the Section of Gastroenterology, Boston Medical Center, Boston, Massachusetts.
2 Boston University School of Medicine, Boston, Massachusetts.
3 Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts.
4 From the Section of Gastroenterology, Boston Medical Center, Boston, Massachusetts; Boston University School of Medicine, Boston, Massachusetts.
5 From the Section of Gastroenterology, Boston Medical Center, Boston, Massachusetts; Boston University School of Medicine, Boston, Massachusetts. Electronic address: [email protected].