Abstract C137: Racial/ethnic disparities in reasons for colonoscopy testing: Contribution of education level and insurance type, US adults, 2019-2023

Abstract Introduction: Black, American Indian/Alaska Native (AI/AN), and Hispanic individuals are more likely to be diagnosed with distant stage colorectal cancer (CRC). Racial/ethnic disparities in diagnosis stage are largely driven by gaps in screening/early detection steps, including whether testing is routine screening vs. diagnostic after symptom onset and whether there is adequate receipt of follow-up after abnormal routine screening. Identifying these unexplored gaps can help inform targeted efforts. Methods: Data from the 2019, 2021, and 2023 nationally representative National Health Interview Survey were pooled to identify 50–75-year-old individuals age-eligible for CRC screening without a prior diagnosis of colon or rectum cancer. Prevalence of self-reported colonoscopy in the past 10 years (alone or in combination with stool testing) and the main reason for this test was estimated by race/ethnicity. Reported reasons of “routine exam” or “follow-up after earlier exam or screening test” were used to operationalize preventative testing and “because of a problem” as diagnostic testing for symptom follow-up. Logistic regression models estimated adjusted prevalence ratios (aPR) comparing race/ethnic groups, adjusted for age, sex, US region, and survey year. Education level and insurance type was explored as a potential mediators to race/ethnic disparities via sequential adjustment analyses. Results: 3999 Hispanic, 28722 non-Hispanic (NH)-White, 4388 NH-Black, 1700 NH-Asian, and 567 NH-AI/AN individuals were age-eligible for CRC screening. Overall, 63.3% reported colonoscopy receipt, with about 82% of these individuals receiving the test as a “routine exam”, 5.3% as a follow-up from an earlier test or screening exam (7% when restricted to those who also had a stool test), and 9.8% “because of a problem”. Colonoscopy testing as a “routine exam” was lower in AI/AN individuals (69.1% vs. 81.6% in White individuals, aPR:0.87, 95% CI:0.8-0.94) while testing “because of problems” was higher for both AI/AN (17.2%, aPR:1.60, 95% CI: 1.20-2.13) and Hispanic (13.4%, aPR:1.30, 95% CI:1.13-1.51) individuals. Conversely, colonoscopy as "follow-up after an earlier exam or screening test" was lower in Black (3.6%, aPR:0.66, 95% CI:0.52-0.84) and Asian (3.1%, aPR:0.51, 95% CI:0.34-0.76) individuals compared to White (5.8%) individuals. Adjustment for education and insurance type attenuated but did not eliminate disparities for Hispanic, AI/AN and Black individuals, whereas adjustment did not alter the magnitude of disparities for Asian individuals. Conclusion: Gaps in whether testing was routine vs. symptom follow up were prominent for AIAN and Hispanic individuals whereas follow-up testing gaps were prominent for Black and Asian individuals. Mediation analysis suggested that improving equitable healthcare access could partially remediate disparities for Hispanic, AI/AN, and Black, but addressing other barriers (linguistic, cultural, knowledge or psychosocial) may be important for Asian individuals. Citation Format: Priti Bandi, Rebecca Landy, Jessica Star, Rebecca Siegel, Larry G. Kessler, Chyke A. Doubeni. Racial/ethnic disparities in reasons for colonoscopy testing: Contribution of education level and insurance type, US adults, 2019-2023 abstract. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C137.