Study Design: Computerized medical records and endoscopy reports will be searched to identify patients older than 80 years old who underwent colonoscopy indicated for average risk screening for colon cancer or surveillance of polyps. A control group of patients between the ages of 50 and 79 will also be identified who underwent colonoscopy indicated for average risk screening for colon cancer or surveillance of polyps. The ratio of controls to study patients will be 2 to 1. Records will be searched from 1997 to July 31, 2006. Data collected will include age at time of colonoscopy, sex, body mass index, a personal history of CAD, DM, CVA, or PVD, endoscopic and histologic findings of colonoscopy, evidence of complete examination, all complications during colonoscopy, evidence of complications after colonoscopy including perforation, bleeding, MI, and CVA. The use of aspirin, NSAIDS, calcium, and vitamin D will be recorded. A comprehensive questionnaire that will include information on diet, exercise, family history, smoking, alcohol consumption, use of aspirin, NSAIDS, calcium, vitamin D, and statins will be administered by the endoscopist prior to colonoscopy.