Associations between Cumulative Environmental Quality and Neural Tube Defects

Abstract

TPS 741: Adverse birth outcomes 2, Exhibition Hall, Ground floor, August 28, 2019, 3:00 PM - 4:30 PM Background/Aims: Neural tube defects (NTD), including anencephaly, spina bifida (SB), and encephalocele, are some of the most severe birth defects. The impact of how cumulative environmental quality contributes to associations with NTDs is unknown. The Environmental Quality Index (EQI) is a comprehensive measure of cumulative environmental exposures for five domains (air, water, land, sociodemographic, built) from 2000-2005. Methods: We conducted a county-level analysis to assess the associations between the EQI and four birth defects (NTD, anencephaly, SB, and encephalocele) using data from the Texas Birth Defects Registry and live birth records from 2000-2006. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated from Poisson regression models between the NTD defects and the EQI, represented by three exposure categories based on percentiles (<50%, or “better” environmental quality; 50-75%, “mid”; >75%, “worst”), adjusted for potential confounders. Results: We observed non-linear trends for overall EQI and the water domain, with increased prevalence of birth defects observed in the mid versus better environmental quality categories. For overall EQI, mid environmental quality was associated with higher prevalence of NTDs [PR=1.27, 95%CI: 1.06, 1.52], anencephaly [1.39 (1.16, 1.66)], SB [1.18 (0.98, 1.42)], and encephalocele [1.34 (1.11, 1.60)], as compared to better environmental quality. In the water domain, mid environmental quality was associated with higher prevalence of each of these four outcomes [NTDs: 1.58 (1.14, 1.78); anencephaly: 2.29 (2.03, 2.57); SB: 1.46 (1.30, 1.65); encephalocele 1.01 (0.90, 1.13)]. Comparing worst environmental quality to better environmental quality for the sociodemographic domain, the PRs were 2.14 (1.93, 2.37) for NTDs, 3.32 (3.00, 3.68) for anencephaly, 1.91 (1.72, 2.12) for SB, and 1.12 (1.00, 1.25) for encephalocele. In the air, land, and built domains, inverse associations were observed with all birth defects studies. Conclusions: We found that sociodemographic factors, water quality, and overall environmental quality contribute to associations with these NTD outcomes, but not with air, land or built environmental quality. This abstract does not reflect EPA policy.