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Studies Prove That Elevated Lead Levels in Children Have a Direct Nexus with Academic Performance

The National Toxicology Program, U.S. Dept of Health and Human Resources, has created a comprehensive report entitled Monograph on Health Effects of Low-Lead, 10/14/2011, peer reviewed November 17-18, 2011. Specifically, this literature makes conclusions on the effects of blood lead levels with a focus on BPb levels less than 10ug/dL.  As described in Section 1.2.2, the NTP’s conclusions were derived by evaluating data from epidemiological studies with a focus on blood Pb levels <10µg/dL.  The evidence is discussed for specific health outcomes within each chapter, and varies by the study design and type of analysis used to examine the relationship of the health outcome with blood Pb across the hundreds of studies evaluated. In some cases, authors restricted the analysis to the population with blood Pb levels <10µg/dL, <5µg/dL, or even lower and the association of the health effect with the blood Pb level is clear.  For example, Lanphear et al. (2000) reported an inverse relationship between blood Pb and academic performance in a cross-sectional study of 4853 children ages 6-16 from the NHANES-III dataset; the association with blood Pb remained significant in further analyses restricted to 4681 children with blood Pb <10µg/dL (p<0.001), and 4043 children with blood Pb <5µg/dL.  In other cases, the authors reported a significant association between blood Pb and an effect in a population with a mean blood Pb level <10µg/dL.   These analyses support an effect of a blood Pb level <10µg/dL, but they do not exclude the possibility that individuals significantly above or below the mean blood Pb level are driving the effect.

As described above, the NTP’s conclusions were derived by evaluating data from epidemiological studies with a focus on blood Pb levels <10µg/dL. The evidence is discussed for specific health outcomes within each chapter, and varies by the study design and type of analysis used to examine the relationship of the health outcome with blood Pb across the hundreds of studies evaluated.  In some cases, authors restricted the analysis to the population with blood Pb levels <10µg/dL, <5µg/dL, or even lower and the association of the health effect with the blood Pb level is clear.  For example, Lanphear et al. (2000) reported an inverse relationship between blood Pb and academic performance in a cross-sectional study of 4853 children ages 6-16 from the NHANES-III dataset; the association with blood Pb remained significant in further analyses restricted to 4681 children with blood Pb <10µg/dL (p<0.001), and 4043 children with blood Pb <5µg/dL.  In other cases, the authors reported a significant association between blood Pb and an effect in a population with a mean blood Pb level <10µg/dL.  In contradiction to Dr. Molofsky’s opinion, the report specifically states, “In children, there is sufficient evidence that blood Pb levels <5µg/dL are associated with increased diagnosis of attention deficit hyperactivity disorder (ADHD), greater incidence of problem behaviors, and decreased cognitive performance as indicated by lower academic achievement and specific cognitive measures” (Bold added)(The National Toxicology Program of the US Department of Health and Human Services, November, 2011).  The Governmental studies show a direct nexus between elevated lead levels and academic performance in adolescents.