Abstract B152: Joint Associations of Neighborhood Socioeconomic Status and Education on the Incidence of Colorectal Cancer: The Multiethnic Cohort Study

Abstract Background: Colorectal cancer (CRC) is the 3rd most diagnosed cancer worldwide. When considered separately, both neighborhood- and individual-level SES exposures have been associated with CRC incidence. However, the joint associations of neighborhood- and individual-level SES on CRC incidence have not been examined. Methods: In a prospective study of 153,725 Multiethnic Cohort (MEC) participants (24,764 African American, 44,447 Japanese American, 34,974 Latino, 11,511 Native Hawaiian, and 38,029 White participants) recruited from predominantly Los Angeles County, California (CA), and Hawaii (HI), we examined the joint association of neighborhood SES (nSES) and individual-level education with CRC incidence (CA: 2,519, HI: 2,210 cases). Education, other demographics, and health behaviors were self-reported in the baseline questionnaire (1993-1996). CRC diagnosis was determined via linkages with state cancer registries. nSES was derived using a composite score based on 1990 US Census block group data and assigned to geocoded baseline addresses. Our joint SES measure included four categories: high nSES (quintiles 4-5) and high education ( high school), high nSES and low education (≤ high school), low nSES (quintiles 1-3) and high education, and low nSES and low education. State-specific hazards ratios (HR) for CRC incidence were estimated for joint SES categories. Cox regression adjusted for age at cohort entry, CRC family history, polyp history, obesity, diabetes, diet, alcohol, smoking, physical activity, and NSAID, multivitamin, and hormone therapy use. Subgroup analyses were conducted by sex, race, and ethnicity. Results: For HI MEC participants, compared to individuals with high nSES and high education, risk for CRC was highest among those with low nSES and low education (HR=1.27; 95% CI:1.11-1.45) followed by high nSES and low education (HR=1.25; 95% CI:1.12-1.41), and low nSES and high education (HR=1.17; 95% CI: 1.03-1.31). This pattern of association was observed across sex but differed across race and ethnicity (p-heterogeneity=0.04). The overall pattern of association was observed among White participants in HI. However, for Japanese American individuals in HI, compared to those with high nSES and high education, risk for CRC was highest for low nSES and high education (HR=1.29; 95% CI:1.09-1.53) and high nSES and low education (HR= 1.28; 95% CI; 1.10-1.50). For Native Hawaiian individuals, compared to those with high nSES and high education, CRC risk was highest for those with low nSES and low education (HR=1.70; 95% CI: 1.20-2.42). Associations were not statistically significant between the joint SES measure and CRC risk in CA (HRs: 0.92-0.97). Conclusion: Among MEC participants in HI, CRC risk varied with the joint measure of nSES and education across racial and ethnic groups. These findings emphasize the importance of considering the joint associations of neighborhood- and individual-level SES in understanding racial and ethnic disparities in CRC. Citation Format: Catherine Walsh, Meera Sangaramoorthy, Songyi Park, Sung-shim (Lani) Park, Gertraud Maskarinec, Lynne Wilkens, Christopher Haiman, Anna Wu, Salma Shariff-Marco, Loic Le Marchand, Iona Cheng. Joint Associations of Neighborhood Socioeconomic Status and Education on the Incidence of Colorectal Cancer: The Multiethnic Cohort Study abstract. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B152.