The Relationship between Early Childhood Blood Lead Levels and Performance on End-of-Grade Tests

Abstract

BackgroundChildhood lead poisoning remains a critical environmental health concern. Low-level lead exposure has been linked to decreased performance on standardized IQ tests for school-aged children.ObjectiveIn this study we sought to determine whether blood lead levels in early childhood are related to educational achievement in early elementary school as measured by performance on end-of-grade (EOG) testing.MethodsEducational testing data for 4th-grade students from the 2000–2004 North Carolina Education Research Data Center were linked to blood lead surveillance data for seven counties in North Carolina and then analyzed using exploratory and multivariate statistical methods.ResultsThe discernible impact of blood lead levels on EOG testing is demonstrated for early childhood blood lead levels as low as 2 μg/dL. A blood lead level of 5 μg/dL is associated with a decline in EOG reading (and mathematics) scores that is roughly equal to 15% (14%) of the interquartile range, and this impact is very significant in comparison with the effects of covariates typically considered profoundly influential on educational outcomes. Early childhood lead exposures appear to have more impact on performance on the reading than on the mathematics portions of the tests.ConclusionsOur emphasis on population-level analyses of children who are roughly the same age linked to previous (rather than contemporaneous) blood lead levels using achievement (rather than aptitude) outcome complements the important work in this area by previous researchers. Our results suggest that the relationship between blood lead levels and cognitive outcomes are robust across outcome measures and at low levels of lead exposure.

The Relationship of Neighborhood Socioeconomic Differences and Racial Residential Segregation to Childhood Blood Lead Levels in Metropolitan Detroit

“…2 Historical and recent research show that there is no safe exposure to lead in children without doing permanent and irreparable neurological, neurobehavioral, and physiological damage. [2][3][4][5][6][7][8][9][10][11][12][13] This damage may include a wide range of problems in children with the most common effect being permanent behavioral and learning deficits such as reduced IQ, ADHD, memory loss, etc. 2 Evidence of this irreparable damage led the Centers for Disease Control and Prevention (CDC) to lower the reference level (previously called the level of concern) for lead poisoning from ≥10 to ≥5 μg/dL in 2012.…”

Blood lead levels of contemporary Japanese children

“…A number of epidemiologic studies done since the 1980s have revealed that Pb impairs normal development of cognitive functions of children [1]. Exposure to Pb has been related to lower intelligence quotient (IQ) [2], poor academic achievement [3], and delinquent behavior [4]. Moreover, concern has recently been raised that adverse effects are seen at exposure levels lower than were considered safe in the past [5,6].…”

Trends in preschool lead exposure, mental retardation, and scholastic achievement: Association or causation?

“…(Byers & Lord, 1943;Marlowe, 1995;David et al, 1976; The negative correlation between blood lead and SAT trends is consistent with research demonstrating an inverse relationship between preschool blood lead and IQ, and research showing IQ is an excellent predictor of academic achievement. (Schwartz, 1994; U.S. Centers for Disease Control and Prevention, 1991;Lanphear et al 2005;Miranda et. al, 2007;Canfield et al, 2003;Neisser et.…”

“…Many studies also show an inverse relationship between blood lead and IQ and academic achievement (U.S. Centers for Disease Control and Prevention, 1991;Lanphear et al 2005;Miranda et. al, 2007).…”