Abstract B152: County-level particulate matter 2.5 exposure associated with higher rates of pediatric leukemia in Southeast Texas

Abstract Background: Exposure to fine particulate matter (PM2.5) is associated with respiratory illness, cardiovascular disease, and cancer. In 2024, the U.S. EPA reduced the annual PM2.5 standard from 15 to 9 µg/m3. Despite this, several counties in southeast Texas remain above this threshold. While the health risks of PM2.5 in adults are well-documented, the role of PM2.5 on childhood leukemia remains inconclusive, particularly in diverse racial/ethnic groups. Objective: To determine whether exposure to PM2.5 is associated with increased incidence of leukemia and acute lymphoblastic leukemia (ALL), and to determine whether these associations differ by race/ethnicity. Methods: We obtained data on incident leukemia diagnoses among people 0-19 years of age across 25 Texas counties from the National Cancer Institute’s SEER 22 database (2000–2021). We categorized counties as high (HPM) or low (LPM) PM2.5 based on the 9 µg/m3 EPA standard. We calculated age-adjusted rate ratios (RRs) and 95% confidence intervals (CIs) using SEER*Stat. We conducted linear regression analyses to examine the association between PM2.5 exposure and leukemia incidence rates, overall and stratified by race/ethnicity. Results: Of 2,418 pediatric leukemia cases identified, Hispanic children represented 52.4% of cases but only 42% of the population. Rate ratios for total leukemia (RR = 1.28; 95% CI: 1.10–1.49) and ALL (RR = 1.35; 95% CI: 1.12–1.64) were higher in HPM vs. LPM counties. When stratified by race/ethnicity, Hispanic children in HPM counties showed significantly elevated leukemia and ALL incidence compared to their LPM counterparts (RR = 1.35; 95% CI: 1.02–1.81). No statistically significant differences were observed in other racial/ethnic groups. Linear regression indicated that ALL incidence increased with county-level PM2.5 exposure among Hispanic, non-Hispanic (NH) Black, and NH Asian children (p<0.05). NH White children also experienced an increase in incidence however it was not significant (p= 0.34). Discussion: Our findings suggest that the association between county-level PM2.5 exposure and childhood leukemia differ by race/ethnicity. Specifically, we consistently observed a significant association between PM2.5 and childhood leukemia among Hispanic children. These results highlight the role of environmental and social determinants of health in pediatric cancer health disparities. Conclusion: PM2.5 concentrations above the EPA annual standard are associated with ALL incidence among Hispanic children in Texas. Racial/ethnic disparities underscore the necessity of tailoring public health interventions to vulnerable populations and improving air quality. Further case-control studies exploring the interplay of air pollution and genetics are warranted. Citation Format: Angel A. Otto, Jeremy M. Schraw, Thanh T. Hoang, Michael E. Scheurer. County-level particulate matter 2.5 exposure associated with higher rates of pediatric leukemia in Southeast Texas [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 B152.