Cooper et al came to a somewhat different conclusion (7). They analyzed 1.8 million Medicare patient colonoscopies in 1999 using ICD-9 codes for rates of polyp detection (pathology was not examined, so it is not clear what percentage of these patients had hyperplastic polyps, adenomas, advanced adenomas, or cancer). They found that the rate of polyp detection decreased with age but was still high (ranging from 15.2-31.3% in patients older than 80). Cooper had previously shown that the incidence of colorectal cancer increased with age in an analysis of all new cases of colon cancer in Medicare patients in 19878. Similarly, the National Polyp Study has shown an increase in the incidence of high grade dysplasia in patients older than 60 (9).