1 Department of Family Medicine, Kaohsiung Veterans General Hospital, Kaohsiung City 81362, Taiwan
2 Department of Public Health, Kaohsiung Medical University, Kaohsiung City 803, Taiwan
3 Division of Colorectal Surgery, Department of Surgery, Kaohsiung Veterans General Hospital, Kaohsiung City 81362, Taiwan
4 Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Veterans General Hospital, 386 Ta-Chung 1 st Road, Kaohsiung City 80424, Taiwan
5 School of Medicine, National Yang-Ming University, Taipei, Taiwan