Dietary risk factors associated with colorectal polyp risk and potential for progression to malignancy.

3626 Background: Colorectal polyp development and progression to cancer are associated with diet and microbial dysbiosis. Red and processed meat intakes have been associated with colorectal polyps, but evidence on probiotic and prebiotic usage is inconclusive. This study examines the association of dietary factors with colorectal adenomas (ADs) and sessile serrated polyps (SSPs) of low and high potential of progression to cancer. Methods: In the Colorectal Molecular Atlas Project, 1082 participants underwent a colonoscopy, and completed a questionnaire. Individuals were classified as polyp-free controls, and polyp cases with high potential for progression to cancer (≥ 1 cm, villous component, high-grade dysplasia, or multiple AD and/or SSPs) or low potential (all other AD or SSP cases). Frequency of dietary intake derived from questionnaire responses was divided into quartiles (total meat, total red meat, total processed meat, chicken, and fish) or no intake/tertiles (total probiotic food: yogurt, kefir, sauerkraut, kimchi, fermented cabbage, kombucha, other fermented beverages). Multinomial logistic regression models were used to derive odds ratios and 95%CI after adjusting for confounders. Results: Highest intake of total meat was associated with increased risk of high progression potential polyps (OR 1.63, 95%CI 1.03-2.60) and sessile serrated lesions (OR 1.60, 95%CI 1.03-2.50) in comparison to lowest intake. Highest intake of red meat was associated with increased risk of high progression potential polyps (OR 1.80, 95%CI 1.16-2.80) and SSPs (OR 1.68, 95%CI 1.10-2.56) in comparison to lowest intake. The second quartile of fish intake was significantly associated with a reduced risk of polyps with low progression potential (OR 0.63, 95%CI 0.44-0.99) and ADs (OR 0.63, 95%CI 0.42-0.96) compared to lowest intake; however, the third and fourth quartiles were not significantly associated with risk. Chicken, processed meat, probiotic food, probiotic supplement, and prebiotic supplement intake were not associated with risk. Conclusions: Dietary risk factors may vary by type of polyp, thus, dietary recommendations should reflect these differences. Increased total and red meat intake may increase risk of polyps with high progression potential and sessile serrated lesions, and fish intake may reduce risk for polyps with low progression potential and adenomas. Probiotics and prebiotics may not be an effective risk reduction strategy.