The impact of low-level lead toxicity on school performance among children in the Chicago Public Schools: a population-based retrospective cohort study

Table 3 Log binomial regression models for the effect of blood lead concentration (B-Pb) on reading failure and math failure

		All children (n = 46,796)		NH white children (n = 4,064)		NH black children (n = 29,736)		Hispanic children (n = 12,996)
Comparison		RR	95% CI	RR	95% CI	RR	95% CI	RR	95% CI
Reading failure
Unadjusted B-Pb (μg/dL)	1 μg/dL increase	1.12	1.11, 1.13	1.17	1.11, 1.23	1.08	1.07, 1.09	1.09	1.06, 1.12
Unadjusted B-Pb (μg/dL)	5 μg/dL increase	1.74	1.66, 1.83	2.19	1.67, 2.87	1.45	1.37, 1.53	1.54	1.36, 1.75
Adjusted^a,b B-Pb (μg/dL)	1 μg/dL increase	1.06	1.05, 1.07	1.14	1.08, 1.20	1.05	1.04, 1.06	1.08	1.05, 1.11
Adjusted^a,b B-Pb (μg/dL)	5 μg/dL increase	1.32	1.26, 1.39	1.93	1.47, 2.54	1.28	1.21, 1.35	1.47	1.29, 1.66
Math failure
Unadjusted B-Pb (μg/dL)	1 μg/dL increase	1.13	1.12, 1.14	1.15	1.09, 1.22	1.08	1.07, 1.09	1.09	1.06, 1.13
Unadjusted B-Pb (μg/dL)	5 μg/dL increase	1.84	1.76, 1.93	2.03	1.51, 2.73	1.47	1.39, 1.55	1.58	1.37, 1.82
Adjusted B-Pb (μg/dL)	1 μg/dL increase	1.06	1.05, 1.07	1.11	1.05, 1.18	1.05	1.04, 1.06	1.09	1.06, 1.12
Adjusted B-Pb (μg/dL)	5 μg/dL increase	1.32	1.26, 1.39	1.71	1.26, 2.30	1.28	1.22, 1.35	1.51	1.31, 1.75

Model Summaries are for Children with B-Pbs Lower than 10 μg/dL, Overall and Stratified by Race/Ethnicity.
^aFor All Races, model includes blood lead concentration (<10 μg/dL), gender, mother’s education, low-income, very low birth weight/preterm, child’s age at time of B-Pb, ISAT vs. Iowa, and race (black vs. white and Hispanic vs. white).
^bFor individual races, model includes blood lead concentration, gender, mother’s education, low-income, very low birth weight/preterm, child’s age at time of B-Pb, ISAT vs Iowa.

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