Abstract A101: Associations of neighborhood environment with colorectal cancer risk across race and ethnicity in the Multiethnic Cohort

Abstract Background The contributing role of the neighborhood environment in colorectal cancer (CRC) disparities is not fully understood. Using data from a large multiethnic study, we compared neighborhood characteristics (unhealthy food environments, high alcohol outlet density, and low walkability) across race and ethnicity and then evaluated whether these characteristics were associated with greater CRC risk. Methods Data for 195,860 Black, Japanese American, Latino, Native Hawaiian, and white participants living in California and Hawaii (CA and HI) came from the prospective Multiethnic Cohort (MEC) Study. Participants’ neighborhoods (census block group) were assessed at study enrollment (1993-1996) using Census and business data. Neighborhood environment characteristics included the retail food environment index, on and off-premises alcohol outlet density per population, and walkability assessed using street connectivity (gamma index) and traffic density. Neighborhood environment variables were grouped into relevant categories (food environment) or based on quintiles (alcohol outlets and walkability). Participants were followed through 2013 for incident invasive CRC via the Surveillance, Epidemiology, and End Results program. Multinomial logistic regression was used to examine associations of racial and ethnic group with neighborhood characteristics, adjusted for study location. Stratified multivariable Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for CRC risk overall and by race and ethnicity, adjusted for age at baseline, sex, years of education, and study location. We tested for heterogeneity by study location before pooling study data and accounted for potential intra-cluster correlation among individuals living in the same neighborhood with a cluster term for neighborhood in the Cox models. Results Compared to white participants, Black participants had higher odds of living in neighborhoods with no food retailers (odds ratio [OR] 1.13, 95% CI 1.08, 1.18) and in neighborhoods with no healthy food retailers (OR 1.08, 95% CI 1.03, 1.15). However, the food retail environment was not associated with CRC risk overall or by racial and ethnic groups. Japanese American participants had statistically significantly lower odds than white participants of residing in neighborhoods with the highest alcohol outlet density (OR 0.59, 95% CI 0.56, 0.59). Alcohol outlet density was associated with CRC risk for Japanese American participants (HR 1.28, 95% CI 1.08, 1.52 for quintile 5 vs. quintile 1); alcohol outlet density was not associated with CRC risk for other racial and ethnic groups. There was no evidence of a statistically significant association between neighborhood walkability with CRC diagnosis overall or for any racial or ethnic group. Conclusion Racial and ethnic groups reside in neighborhoods with different characteristics and the neighborhood environment may pose different risks for CRC incidence across race and ethnicity. Citation Format: Courtney M. Hill, Iona Cheng, Katherine Lin, Salma Shariff-Marco, Meredith AJ. Hullar, Trang VoPham, Marie Spiker, Donald L. Chi, Chris Haiman, Lynne R. Wilkens, Loïc Le Marchand, Amanda I. Phipps. Associations of neighborhood environment with colorectal cancer risk across race and ethnicity in the Multiethnic Cohort [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 A101.