ASPO Abstracts
Type 2 diabetes is associated with increased incidence of colorectal cancer among low SES and non-Hispanic Black cohort participants
Category: Cancer Health Disparities
Conference Year: 2023
Abstract Body:
Purpose of the study: Type 2 diabetes and colorectal cancer (CRC) disproportionately burden Americans of lower SES. We evaluated the association between diabetes and CRC risk in a cohort primarily composed of low SES and Black participants. Methods: Data arose from 74,827 participants of the Southern Community Cohort Study, of which 901 were diagnosed with incident CRC after study enrollment, 68% were non-Hispanic Black, and 56% had household income <$15,000 at enrollment. Self-reported diabetes status was obtained through questionnaires at enrollment and three follow-up interviews; a subsample comparison with medical records found sensitivity = 96%. Cox proportional hazards were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between diabetes and CRC risk. Statistical models included adjustment for enrollment source, race, sex, screening history, health insurance status, smoking, education, income, alcohol, BMI, and family history of CRC. Results: Approximately 36% of the cohort reported prevalent or incident diabetes during the study period and the frequency was higher among participants with lower household income. Diabetes was associated with increased incidence of CRC where prevalent diabetes at baseline was associated with HR of 1.34 (95%CI:1.14,1.57). Analyses restricted to participants eligible for CRC screening and who reported undergoing screening for CRC and diabetes showed stronger associations between prevalent diabetes and increased CRC risk (HR=1.52; 95%CI:1.11,2.07). Associations were consistent across anatomic site where the prevalent diabetes HR for colon cancer was 1.37 (95%CI:1.14,1.64) and 1.24 (95%CI:0.89,1.73) for rectal cancer. Incident diabetes was also associated with increased CRC risk, although the strength of association was attenuated (HR=1.12; 95%CI:0.97,1.29). The positive association was strongest among participants diagnosed with diabetes within five years of incident CRC. Associations did not differ by sex, race, BMI or smoking status. Conclusions: Our findings support an association between diabetes and increased CRC risk. Public health interventions focused on low SES populations may decrease disparities in diabetes and CRC.
Keywords: Colorectal Cancer, Diabetes, Cancer Health Disparities, Non-Hispanic Black, SES