Doctor Murata's work experience: May 2001-Apr 2002, Depart of Medicine, Kyusyu Rosai Hosptial; May 2002-Apr 2003, Depart of Medicine, Kyushu University hospital; May 2003-Apr 2004, Depart of Gastroenterology, Chikuho Social Insurance Hospital; May 2004-Mar 2007, Depart of Gastroenterology, Aso IIzuka hospital; Apr 2007-Mar 2008, Depart of Gastroenterology, Saiseikai Fukuoka General Hospital; Apr 2008-Mar 2009, Depart of Gastroenterology, Fukuoka Higashi Medical Center; Apr 2009-Present, Department of Preventive Medicine and Community Health, School of Medicine, University of Occupational and Environmental Health.