DESCRIPTION (Applicant's Description) A case-control study of adenomatous polyps was conducted between 1991 and 1994 as part of the Minnesota Cancer Prevention Research Unit (CPRU) (PO1 CA50305). This study collected extensive data on demographics and lifestyle factors, family history, medical history, and dietary data on 574 incident adenomatous polyp cases, 707 polyp-free controls, 550 community controls, 538 sigmoidoscopy negative controls, and 219 incident hyperplastic polyp cases. During the early stages of this study, questions arose in the colon cancer and adenomatous polyp literature which were of interest and additional data were collected on aspirin and non-steroidal anti-inflammatory medication (NSAID) use and meat preparation methods. Data will also be available, from a separately funded study (RO1 CA59045), on the acetylator (NAT2) genotype of these case-control participants. At the conclusion of the study, it was also noted that a significant number of incident hyperplastic polyp cases had been identified. It was decided that these should be analyzed separately from the polyp-free control group. A sub-study to collect data on sigmoidoscopy-screened individuals was also conducted to help model the amount of referral bias that could potentially occur in this colonoscopy-screened population. The goal of this project is to analyze this case-control population on these new areas and also to undertake an analysis combining all data to distinguish differences between early and late stage risk factors in colon carcinogenesis. We propose analyses in the following areas: 1) aspirin/NSAIDs and adenomatous polyps; 2) meat preparation methods and NAT2 genotype and adenomatous polyps; 3) risk factors for hyperplastic polyps; 4) referral bias issues and methodology; and 5) a multivariate analysis taking into account a variety of known and suspected risk factors for hyperplastic and adenomatous polyps.