Identifying High-Risk ZIP Codes for Childhood Lead Exposure: A Statewide ZCTA-Level Priority List for North Carolina

Abstract

Research has consistently shown that there is no safe blood lead level (BLL) for children. Despite progress in lead poisoning prevention, lead exposure remains a persistent threat to the health and neurological development of children. To identify high-risk ZIP codes for use by families and health care providers for the entire state of North Carolina, we developed a risk model using ZIP Code Tabula­tion Area (ZCTA)-level census data. We obtained all available BLL testing data from the North Carolina Department of Health and Human Services for the years 2010–2015 via data use agreement. We fit a multivariable regression model with the ZCTA-level mean of log normalized BLLs as the de­pendent variable and ZCTA-level census data for known risk factors of childhood lead exposure as predictors. We used this model to create a priority risk categorization. We organized ZCTAs into 20 quantiles, or priority risk categories, that can be used in local and statewide screening programs. The first six (of 20) quantiles were identified as particularly high-risk areas for childhood lead exposure. Because BLL testing is not universal, the BLL testing data used in this study are likely biased toward those most at risk for lead exposure. This study demonstrates the utility of ZCTA-level census data in identifying high-risk ZIP codes for childhood lead exposure, which can be used to ensure that the highest-risk children are tested in a timely manner. This approach can be replicated to address lead exposure nationally.