Inclusion Criteria:

- Only asymptomatic ethnic Chinese subjects aged 50 years or older who underwent total
colonoscopy were included in this study

Exclusion Criteria:

- Persons with symptoms indicative of colorectal cancer, such as hematochezia, body
weight loss, development of persistent abdominal pain or rectal pain, and a change in
bowel habit, were excluded from this study. Other exclusion criteria were: (1) past
history of CRC, colon polyps, or inflammatory bowel disease; (2) a history of
screening tests, including FOBT, sigmoidoscopy, colonoscopy, or barium studies within
5 years; (3) any first degree relative(s) with colon cancer; (4) criteria for
hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis, or other
polyposis syndrome; (5) obvious anemia with hemoglobin level less than 10g/dl; (6)
incomplete examination of entire colon, including poor colon preparation and failure
to reach cecum.