Association between environmental burden and cancer incidence rates across population subgroups in the United States (US).

11009 Background: With more than 2 million projected new cancer diagnoses in 2025 in the US alone, many studies have linked environmental pollutants to carcinogenesis. However, they often examine exposures in isolation, overlooking the complexity of real-world multi-exposure conditions. In this study, we investigate the impact of multiple simultaneous environmental exposures on cancer incidence rates at the county level. Methods: Data on environmental burden (for e.g. air and water pollution, toxic sites, built environment), measured using the Environmental Burden Module (EBM), were obtained from the CDC Environmental Justice Index. County-level cancer incidence rates for breast, pancreas, prostate, lung, colon, and all cancers combined were obtained from the CDC State Cancer Profiles. Multivariable linear regression models estimated the effects of EBM quartiles (Q1 as the reference, representing the lowest burden, and Q4 noting highest) on cancer incidence rates for the total population and stratified by urbanicity, sex, and age. Interaction terms between EBM quartiles and demographic variables (sex and age) were significant (p < 0.05). All results are presented as cases per 100,000 population. Results: Higher environmental burden was associated with increasing incidence rates for all cancers in Q3 (15.61 [9.45, 21.78]) and Q4 (7.87 [1.59, 14.15]) across all US counties. Breast (4.45; 95% CI [2.10, 6.80]) and prostate cancer (2.57 [1.00, 4.78]) noted strongest association in Q4. Similarly, rural counties too showed increased rates of all cancers with increasing environmental burden (Q3: 18.22 [10.56, 25.88]); Q4: 21.15 [7.41, 34.89]). In urban counties, prostate cancer incidence was higher in Q4 (4.65; [0.08, 9.22]). Among males, lung cancer incidence increased significantly in the most environmentally burdened counties (Q4: 0.45 [0.21, 0.89]). For colon cancer, while incidence rate for males decreased significantly (Q4: -0.45 [-0.91, -0.01]), it increased among females in the most environmentally burdened counties (Q4: 21.15 [14.21, 28.18]). For older individuals ( > 65y), Higher rates of all cancers combined were found in Q3 (125.70 [76.95, 174.44]) and Q4 (117.15 [68.04, 166.26]). Lung cancer incidence was especially sensitive to environmental burden – higher rates were observed in Q2 (3.99 [0.12, 7.87]), Q3 (4.88 [1.49, 8.28]), and Q4 (4.73 [1.56, 7.91]). Conclusions: Greater environmental burden was associated with increased cancer incidence rates across several cancer types with sociodemographic variation. These results indicate the need for regulatory policy and infrastructural investment aimed at mitigating these risks in targeted communities. Further research with higher-resolution data is needed to elucidate these associations and underlying etiologic mechanisms.