EPID-29. ASSOCIATIONS BETWEEN PM2.5, VEGETATION DENSITY AND CHILDHOOD BRAIN TUMORS: A CASE-CONTROL REGISTRY-BASED STUDY FROM TEXAS 1995-2011

Abstract

Abstract BACKGROUND Air pollution has been reported to be associated with childhood leukemia, and increasing vegetation density (greenness) has been inversely associated with adult cancer incidence. However, the interplay between air pollution and greenness in childhood brain tumor (CBT) etiology is unclear. We sought to estimate the association between prenatal exposure to air pollution, greenness, and CBTs in Texas (1995-2011). Materials and METHODS We included 1,316 individuals with a CBT diagnosed ≤ 16 years of age and 109,762 age- and sex-matched controls. We linked birth certificate residential address to census tract annual average particulate matter 2.5 µg/m³ (PM2.5) and Normalized Difference Vegetation Index (NDVI) to approximate prenatal exposure to air pollution and greenness. We estimated odds ratios (OR) and 95% confidence intervals (95% CI) between CBTs, PM2.5 and NDVI interquartile range (IQR) increases. Models were adjusted for birth year, sex, race/ethnicity, and area-level socioeconomic status. RESULTS Ependymoma (n=136), astrocytoma (n=619), medulloblastoma (n=187), PNET (n=57), ATRT (n=54), and other gliomas (n=263) were included. Average birth year PM2.5 and NDVI exposure levels were similar in cases and controls, 11 µg/m³ and 0.4, respectively. Each IQR increase (2.6µg/m³) in PM2.5 was associated with ependymoma (OR: 1.27, 95% CI: 1.01-1.60), adjusting for NDVI. After adjusting for PM2.5 quartiles, each IQR increase in NDVI (0.13) was inversely associated with ependymoma in those diagnosed at 0-4 years of age (OR: 0.75, 95% CI: 0.56-0.97) and medulloblastoma in those aged 0-16 years at diagnosis (OR: 0.75, 95% CI: 0.62-0.91). There was no evidence of statistical interaction for any CBT. CONCLUSIONS Increasing air pollution during the prenatal period increased risk of childhood ependymoma, independent of greenness. Conversely, increasing greenness prenatal exposure decreased the risk of ependymoma and medulloblastoma, independent of PM2.5. These findings highlight the complex relationship between air pollution and greenness in CBT etiology.