The relationship between early childhood blood lead levels and performance on end-of-grade tests.
BACKGROUND
Childhood 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.


OBJECTIVE
In 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.


METHODS
Educational 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.


RESULTS
The discernible impact of blood lead levels on EOG testing is demonstrated for early childhood blood lead levels as low as 2 microg/dL. A blood lead level of 5 microg/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.


CONCLUSIONS
Our 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.
Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina 27708-0328, USA. mmiranda@duke.edu
Marie Lynn
ML
Miranda
Dohyeong
D
Kim
M Alicia Overstreet
MA
Galeano
Christopher J
CJ
Paul
Andrew P
AP
Hull
S Philip
SP
Morgan
D001077:Aptitude Tests; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004521:Educational Measurement; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000097:blood / Q000633:toxicity*; D005260:Female; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood / Q000633:toxicity*; D008297:Male; D009657:North Carolina / Q000453:epidemiology; D012574:Schools
D004785:Environmental Pollutants; D007854:Lead