Moderate lead exposure and elementary school end-of-grade examination performance

Abstract

PurposeThis study investigated the association between moderate lead poisoning in early childhood with performance on a comprehensive set of end-of-grade examinations at the elementary school level in two urban school districts. MethodsChildren born between 1996 and 2000 who resided in Milwaukee or Racine, WI, with a record of a blood lead test before the age of 3 years were considered for the analysis. Children were defined as exposed (blood lead level ≥10 and <20 μg/dL) or not exposed (BLL < 5 μg/dL). Parents of eligible children were mailed surveys to consent to participation and elicit information on potential confounders. On consent, children were matched to educational records for fourth grade Wisconsin Knowledge and Concepts Examinations. Seemingly unrelated regression was used to evaluate the relation between scaled scores on all sections of the examination (math, reading, language arts, science, and social studies) with exposure status, controlling for demographics, social status indicators, health indicators, and district-based poverty indicators. ResultsA total of 1133 families responded to the survey and consented to have educational records released; 43% of children were considered exposed. After controlling for demographic and socioeconomic covariates, lead exposure was associated with significantly lower scores in all sections of the Wisconsin Knowledge and Concepts Examinations (range: science, β = −5.21, P = .01; reading, β = −8.91, P = .003). Children who were black, had a parent with less than a high-school education, and were classified by parents as having less than excellent health had significantly lower performance on all examination components. ConclusionsChildren with moderate lead poisoning in early childhood performed significantly lower on all components of elementary school end-of-grade examinations compared with unexposed children. Household level social status and childhood health indicators partially explain decreased examination scores.