Abstract A146: Structural racism and lung cancer risk: The multiethnic cohort study and Southern community cohort study

Abstract Background: Despite declining incidence rates of lung cancer in the U.S., racial/ethnic disparities persist, highlighting the need to examine structural and social drivers. We investigated associations of structural racism and neighborhood disinvestment with lung cancer risk in two large prospective cohort studies. Methods: Among 137,639 African American, Latino, Japanese American, and Native Hawaiian participants in the Multiethnic Cohort (MEC) Study recruited in 1993-1996 and 47,638 African American participants in the Southern Community Cohort Study (SCCS) recruited in 2002-2009, baseline addresses were geocoded and appended with 1990 (MEC) and 2000/2010 (SCCS) census tract (CT)-level metrics of redlining; racial/ethnic bias in mortgage lending; Index of Concentration at the Extremes for race/ethnicity, education, and income; and percent poverty. Cox proportional hazard models estimated hazard ratios (HR) and 95% confidence intervals (CI). Follow-up time was calculated from age at cohort entry to age at first occurrence of lung cancer diagnosis, death, or end of follow-up (December 31, 2019). Separate models were run for the MEC and SCCS. Base models included strata for categories of age at cohort entry, sex, and race/ethnicity and adjustment for state of residence, clustering by CT, and source of recruitment (for SCCS). A second model additionally included smoking status, quantity, and time dependent quitting. A final model further included select lung cancer risk factors such as education, body mass index, and diet. Results: Over an average follow-up of 20.3 years for the MEC and 12.0 years for the SCCS, 8,229 incident lung cancers occurred. In base models, lung cancer risk was elevated for those living in the highest areas of lending bias (HR=1.46, 95% CI=1.05-2.03) among Native Hawaiian MEC participants, and lending bias (HR=1.28, 95% CI=1.01-1.62) and redlining (HR=1.94, 95% CI=1.02-3.66) among African American SCCS participants, relative to those in the lowest areas. Residence in areas with concentrations of high education or high income reduced lung cancer risk by 14% and 20% in the MEC, and 35% and 39% in the SCCS, respectively, compared to areas with concentrations of low education or low income. In contrast to areas of concentrated low income, minoritized residents, residing in areas of concentrated high income, non-Hispanic White residents reduced risk among Japanese American MEC participants (HR=0.82, 95% CI=0.69-0.97) and African American SCCS participants (HR=0.59, 95% CI=0.42-0.84). Living in areas with ≥20% versus 5% poverty increased risk in both the MEC (HR=1.24, 95% CI=1.12-1.37) and SCCS (HR=1.99, 95% CI=1.20-3.30). Adjustment for smoking attenuated associations toward the null in both cohorts. In fully adjusted models, only the association with lending bias among Native Hawaiian MEC participants remained. Conclusion: These findings suggest that structural racism and poverty affect lung cancer risk and that smoking largely explains the relationship between these structural and social drivers and lung cancer development. Citation Format: Meera Sangaramoorthy, Katherine Lin, Yuhong Zhou, Cherie Guillermo, Mimi Ton, Dian Gu, Pushkar Inamdar, Jun Wu, Kirsten Beyer, Mindy C. DeRouen, Alexandra M. Binder, Daniel Stram, Scarlett L. Gomez, Salma Shariff-Marco, Lynne Wilkens, Loïc Le Marchand, Melinda C. Aldrich, S. Lani Park, Iona Cheng. Structural racism and lung cancer risk: The multiethnic cohort study and Southern community cohort study 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 A146.