Lead brownfields and birth defects in North Carolina 2003–2015: A cross-sectional case–control study
This subproduct examines associations between proximity to lead contaminated brownfields and specific birth defects and groups of birth defects, advancing knowledge on these connections and building pathways in which remediation and restoration of these sites could provide benefits to human health.
Background
Brownfields are a multitude of abandoned and disused sites, spanning many former purposes. Brownfields represent a heterogenous yet ubiquitous exposure for many Americans, which may contain hazardous wastes and represent urban blight. Neonates and pregnant individuals are often sensitive to subtle environmental exposures. We evaluate if residential exposure to lead brownfields is associated with birth defects.
Methods
Using North Carolina birth records from 2003-2015, we sampled 169,499 births within 10 kilometers (km) of a lead brownfield with 3,255 cardiovascular, central nervous, or external defects identified. Exposure was classified by binary specification of residing within 3,000 meters (m) of a lead brownfield. We utilized multivariable logistic regression models adjusted for demographic covariates available from birth records, and 2010 Census to estimate odds ratios (OR) and 95% confidence intervals (CI). Effect measure modification was assessed by inclusion of interaction terms and stratification for the potential modifiers of race/ethnicity, diabetes status, and water source type.
Results
We observed positive associations between cardiovascular birth defects and lead brownfield exposure, OR (95%CI): 1.15 (1.04, 1.26), with suggestive positive associations for central nervous: 1.16 (0.91, 1.47) and external defects 1.19 (0.88, 1.59). We did not observe evidence of effect measure modification by race/ethnicity (LRT p-value 0.21). We did observe modification by diabetes status (LRT p-value 0.05) and water source type (LRT p-value 0.02).
Conclusions
Our results indicate that residential proximity to lead brownfields is associated with birth defects. In-depth analyses of individual defects and other contaminants or brownfield site functions may reveal additional novel associations.