Abstract B90: Diabetes and the risk of colorectal adenomas: Black Women's Health Study

Abstract

Abstract Introduction: Metabolic abnormalities associated with diabetes mellitus (DM) are hypothesized as colorectal carcinogenesis mediators. Results from epidemiologic studies on the association of DM with colorectal cancer are inconclusive. However, limited data from small case-control studies suggests a stronger association of diabetes with colorectal adenoma. Given the relative lack of information on the risk of colorectal adenomas in African-American women, and the higher prevalence of diabetes in African Americans we investigated DM as a risk factor for colorectal adenomas in the Black Women's Health Study. Methods: We conducted a nested case-control study among participants in the Black Women's Health Study - a cohort study of 59,000 women followed biennially since 1995. Cases were defined as women diagnosed with incident colorectal adenoma between 1997 and 2009. Only those adenoma cases verified by medical record review were included. Controls were participants who also underwent lower gastrointestinal endoscopy in the same period and in whom no adenoma or other polyp was found. DM and insulin use were self-reported by participants on each biennial questionnaire. Using logistic regression models, we obtained odds ratios (OR) for colorectal adenoma in relation to DM, adjusting for age, education, body mass index, physical activity, fruit and vegetable intake, family history of colorectal cancer, smoking, alcohol intake, energy intake, and aspirin use. Results: There were 742 adenoma cases and 14,434 non-cases. After adjusting for multiple covariates, there was no association of DM with colorectal adenomas (OR: 1.02, 95% CI: 0.82–1.26) in this study of African-American women. Insulin therapy for DM was also not associated with adenoma risk. Compared to women without DM, the ORs (95% CI) for diabetic women using insulin, and those not using insulin were 1.14 (0.78–1.68) and 0.98 (0.78 − 1.25), respectively. Conclusions: We did not find an association of DM with colorectal adenomas among African-American women. Our results support the findings from two recent cohort studies that showed no association of type 2 DM with colorectal cancer in women. Further research is needed to confirm these findings in African American women, and explore the association of DM and colorectal adenoma in African-American men. Citation Information: Cancer Prev Res 2011;4(10 Suppl):B90.