310. Yogurt Intake and Colorectal Cancer Incidence Subclassified by Bifidobacterium Status in Tumor

BACKGROUND: Although epidemiological evidence is limited, experimental data indicated a tumor-suppressive effect of yogurt containing Bifidobacterium. We hypothesized that the association between yogurt intake and colorectal cancer incidence differed by Bifidobacterium status in tumor tissue. METHODS: We utilized data from two prospective cohort studies: the Nurses’ Health Study and the Health Professionals Follow-up Study. Inverse probability weighted multivariable Cox proportional hazards regression was used to assess differential associations of yogurt intake with the incidence of colorectal carcinomas subclassified by tumor Bifidobacterium status. RESULTS: During follow-up of 132,056 individuals, we documented 2,950 incident colorectal cancer cases, including 1,191 with available Bifidobacterium data. The association between yogurt intake and colorectal cancer incidence differed by Bifidobacterium status (P(heterogeneity) = 0.03). This differential association became stronger in a subgroup analysis of proximal colon cancer (P(heterogeneity) = 0.003). Multivariable hazard ratios in individuals who consumed ≥ 2 servings/week (vs. < 1 serving/month) of yogurt were 0.43 [95% confidence interval (CI), 0.22-0.85] for Bifidobacterium-positive proximal colon cancer, and 1.40 (95% CI, 0.95-2.05) for Bifidobacterium-negative proximal colon cancer. CONCLUSION: Yogurt intake was inversely associated with the incidence of Bifidobacterium-positive (but not Bifidobacterium-negative) proximal colon cancer, suggesting an interactive influence of yogurt intake and intestinal microbiota on tumor development. DISCLOSURES: All Authors: No reported disclosures