Abstract B010: Tobacco retailer density and cancer incidence in California (2016-2020)

Abstract Introduction: Tobacco retailer density is positively associated with smoking prevalence and secondhand smoke exposure—both established risk factors for cancer. However, few studies have examined whether living in areas with higher tobacco retailer density is directly associated with incidence of tobacco-related cancers. This ecological study investigates the association between county-level tobacco retailer density and incidence of tobacco-related cancers in California. Methods: We linked 2016–2020 tobacco retailer data from the California Department of Tax and Fee Administration with incidence data from the California Cancer Registry for six cancers where tobacco use is a major risk factor (bladder, kidney, liver, lung, oral-pharyngeal, pancreas). Tobacco retailer density was defined as the 5-year average number of state-licensed retailers in each county per 1,000 residents. We used quasi-Poisson regression models with age-, sex-, and race/ethnicity-specific case counts at the census tract level, population count as the offset term, and clustering by county to estimate associations between incidence rate ratios (IRRs) and tobacco retailer density. Models adjusted for age, race/ethnicity, sex, and county-level measures for neighborhood deprivation and White-Black income inequality. Stratified analyses were conducted by race/ethnicity, and geographically weighted regression (GWR) models were used to assess spatial heterogeneity in associations. Results: Adjusted quasi-Poisson models indicated a significant positive association between tobacco retailer density and oral cancer incidence (IRR = 1.24, 95% CI: 1.08–1.43). We did not observe statistically significant associations for other cancer sites. Although formal tests for interaction by race/ethnicity were not statistically significant, stratified models revealed significant associations with increased incidence of oral cancer among non-Hispanic (NH) Black (IRR = 3.65, 95% CI: 1.38–9.63) and NH Asian American/Native Hawaiian/Pacific Islander (AANHPI) individuals (IRR = 5.19, 95% CI: 2.47–10.89), and similarly elevated risks for lung and liver cancer. GWR models demonstrated that associations were also geographically clustered, with stronger associations observed in northern and central California. Conclusion: This study is among the first to observe a direct association between tobacco retailer density and incidence of tobacco-related cancers, with disproportionate impacts among NH Black and AANHPI populations. The findings suggest that the spatial distribution of tobacco retailers may function as a structural driver of cancer inequities—independent of Black-White income inequality and neighborhood deprivation. Public health policies aimed at reducing tobacco retailer density could be associated with downstream reductions in cancer burden, especially for historically marginalized populations. Future research should further investigate how neighborhood context—including ethnic enclaves, segregation patterns, and historical redlining—shapes these associations. Citation Format: Alice Guan, Mimi T. Ton, Alison J. Canchola, Arzoo Alam, Shawna Follis, Ann Hsing, Nina C. Schleicher, Trent Johnson, Lisa Henriksen, Scarlett L. Gomez. Tobacco retailer density and cancer incidence in California (2016-2020) [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 B010.