Claim: Kids living near ‘toxic waste sites’ get more lead, may have lower IQs

No kids were tested for IQ! So how do they know higher lead levels are even statistically associated with lower IQs?

The media release is below.

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Children living near toxic waste sites experience higher blood lead levels resulting in lower IQ

Mount Sinai researcher estimates that lead exposure could cause mental retardation in 6 in 1,000 children living near the sites

May 6, 2013 /Press Release/ –– Children living near toxic waste sites in lower and middle income countries such as India, Philippines and Indonesia may experience higher blood lead levels, resulting in a loss of IQ points and a higher incidence of mental retardation, according to a study presented today by Kevin Chatham-Stephens, MD, Pediatric Environmental Health Fellow at the Icahn School of Medicine at Mount Sinai, at the Pediatric Academic Societies (PAS) annual meeting on May 6 in Washington, DC.

The study titled, “The Pediatric Burden of Disease from Lead Exposure at Toxic Waste Sites in Low and Middle Income Countries in 2010,” was a joint research partnership between Mount Sinai and the Blacksmith Institute.

Researchers measured lead levels in soil and drinking water at 200 toxic waste sites in 31 countries then estimated the blood lead levels in 779,989 children who were potentially exposed to lead from these sites in 2010. The blood lead levels ranged from 1.5 to 104 µg/dL, with an average of 21 µg/dL in children ages four years and younger. According to Dr. Chatham-Stephens, first author of the study, these higher blood lead levels could result in an estimated loss of five to eight IQ points per child and an incidence of mild mental retardation in 6 out of every 1,000 children.

“The average blood lead level in an American child is approximately 1.3 µg/dL,” said Dr. Chatham-Stephens. “Our research found an average predicted blood lead level of 21 µg/dL, which is very high. Lead has serious, long-term health consequences such as the potential to impair cognitive development in children and cause mental retardation.” The condition of mental retardation is defined as having an IQ below 70.

“On a global level, this analysis highlights the importance of assigning more public health resources to identify, evaluate and remediate lead-contaminated toxic waste sites in these countries,” said Philip Landrigan, MD, MSc, Dean for Global Health at the Icahn School of Medicine at Mount Sinai, one of the authors of the study. “In order to prevent further detrimental effects on neurodevelopment in children, these countries should create programs to identify toxic wastes and reduce lead exposure.”

“This study is important because, to our knowledge, the burden of disease from these toxic waste sites has never been calculated before,” said Dr. Chatham-Stephens. “We are showing that children who were chronically exposed to toxic waste sites in lower and middle income countries could have had high lead blood levels.”

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3 responses to “Claim: Kids living near ‘toxic waste sites’ get more lead, may have lower IQs

  1. “Researchers measured lead levels in soil and drinking water at 200 toxic waste sites in 31 countries then estimated the blood lead levels in 779,989 children who were potentially exposed to lead from these sites in 2010. The blood lead levels ranged from 1.5 to 104 µg/dL, with an average of 21 µg/dL in children ages four years and younger.”

    Emphases added.

    That’s supposed to be a way to conduct an epidemiological assessment? Not drawing samples to assess blood lead levels in even a representative sample of the at-risk population, nor conducting Stanford-Binet (IQ) testing to correlate those study subjects’ performance, but simply inferring “the burden of disease from these toxic waste sites” on the basis of what the investigators had assumed it ought to be?

    “According to Dr. Chatham-Stephens, first author of the study, these higher blood lead levels could result in an estimated loss of five to eight IQ points per child and an incidence of mild mental retardation in 6 out of every 1,000 children.”

    So what are the limits of accuracy in Stanford-Binet testing among these study populations, and are those limits not greater than “five to eight IQ points”?

    This thing got past peer review to be presented at a convocation of a putatively scientific society?

  2. Coach Springer

    You can fit a lot under the word “may.” Kids with lower IQs may be the mentally disabled offspring of far superior aliens being implanted in unsuspecting earth mothers. — Or “may” not be.

  3. Westchester Bill

    As I understand the literature, the lead IQ link was based on a study of the teeth of children. IQ is negatively related to agressiveness. Aggressive children are more likely to chew on window sills and acquire lead thereby. A major problem with simple correlations is in nailing down what causes what. My theory is that lower IQ causes more chewing on window sills, which chewing leads to more lead in teeth.

    Lead was removed from gasoline decades ago. So why did we need no-child-left-behind?

    If we were to actually measure mean IQ among groups in these studies, we could test better the relation between lead burden in blood and cognition as children do not chew on waste dumps and, in general, poor people live in undesirable neighborhoods mitigates the social class problem in exposure studies.

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