Lead exposure is an on-going children's health problem, especially for children living in urban environments with older housing, soil and water contamination. Low-level lead exposure has been linked to decreased performance on standardized tests for school-aged children and should inform intervention and school readiness policy. The aim of this study was to further explore the association between early childhood blood lead levels and academic achievement in the Chicago Public Schools.

Three administrative datasets, blood lead testing, birth registry and educational testing data for 3^rd grade students born between 1994 and 1998 in Chicago, tested for lead exposure and enrolled in the Chicago Public Schools were linked and then analyzed using exploratory, multivariable linear regression and binomial regression statistical methods.

Early childhood blood lead levels, below 10 μg/dL, are strongly and significantly associated (p<.0001) with worsening academic achievement among third graders in the Chicago Public Schools as measured by the Illinois Standard Achievement Tests for math and reading, controlling for other variables associated with academic achievement including gender, poverty, race/ethnicity, maternal education, and very low birth weight/very pre term births. Additionally, blood lead levels in this range are also associated with a significant increase in failure rates on the third grade reading and math test.

Elevated blood lead levels below 10 mcg/dL are associated with higher rates of school failure and lower rates of school success. This is a significant problem for the Chicago Public School system where mean blood lead levels among the student population remain high, above 5 μg/dL in some populations. This problem is likely to exist for many other large public school systems with a student population that has been exposed to lead, and may explain a portion of disparity in academic achievement.