1. Division of Gastroenterology & Hepatology, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH 44109, USA
2. Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Harvard Medical School, Charlestown, MA 02129, USA
3. Division of Gastroenterology, Massachusetts General Hospital, Boston, MA 02114, USA
4. Division of Gastroenterology & Hepatology, Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA 30912, USA
5. Faculty of Medicine, University of Vic-Central University of Catalonia, 08500 Vic, Spain