Claim: Childhood lead exposure associated with lower IQ, socioeconomic status nearly 3 decades later

Lead hysteria was borne out of “science” that the University of Pittsburgh found was “difficult to explain as honest error.” Nothing has changed.

Here’s a 2001 of mine on the junk science origins of lead hysteria.

This study is just more in the same vein of junk science. A weak association epidemiology effort to blame a supposed slightly lower population IQ on lead vs the actual and far more probable causes — poverty, poor education and other developmental factors.

More on the Needleman controversy in the American Journal of Public Health.

The media release is below. The study is here.

Childhood lead exposure associated with lower IQ, socioeconomic status nearly 3 decades later


Children who had higher blood lead levels at age 11 were more likely to have lower cognitive function, IQ and socioeconomic status when they were adults at age 38, according to a study published by JAMA.

Exposure to lead in childhood may adversely affect brain health and disrupt cognitive development. It is unknown if this disruption results in cognitive decline and altered socioeconomic trajectories by midlife. Aaron Reuben, M.E.M., of Duke University, Durham, N.C., and colleagues conducted a study that included participants of the Dunedin Multidisciplinary Health and Development Study, an investigation of health and behavior of individuals born between April 1972 and March 1973 in Dunedin, New Zealand. Childhood lead exposure ascertained as blood lead levels were measured at age 11 years. High blood lead levels were observed among children from all socioeconomic status levels in this group.

Of 1,037 original participants, 1,007 were alive at age 38 years, of whom 565 (56 percent) had been lead tested at age 11 years. Among the findings:

Childhood blood lead level was associated with lower adult IQ scores nearly three decades later, reflecting cognitive decline following childhood lead exposure.

Childhood blood lead level was associated with lower adult socioeconomic status, reflecting downward social mobility following childhood lead exposure.

The relationship between childhood lead exposure and downward social mobility by midlife was partially but significantly mediated by cognitive decline following childhood lead exposure.
“The results indicate that childhood exposures to lead can be linked with cognitive and socioeconomic outcomes detectable more than 3 decades later,” the authors write.

“For communities that have experienced collective lead exposure events and for countries where lead exposures are still routinely above health standards, the findings raise questions about the reasonable duration and magnitude of public responses. Just as the problem of toxic lead exposure in homes appears to persist, so too do the poor outcomes associated with such exposure. Short-lived public responses to community lead exposure may not be enough.”


7 thoughts on “Claim: Childhood lead exposure associated with lower IQ, socioeconomic status nearly 3 decades later”

  1. did Michael Mann study methodology under this guy?? The parallels between this lead study and AGW are truly eye opening.

    The lead study apparently did no statistical controls for family income level, educational quality of their schools, ethnic IQ differences (yes, they do exist), and other confounding factors. That immediately puts it in the junk science column along with unequal pay and other stupidities.

    I worked on, drove, stood next to running, and pumped gasoline for, lead burning cars all through my youth into my teens and twenties. I have a measured IQ of 130 so I guess I was supposed to have an IQ of 160 and the lead retarded me. Bummer.

  2. That business with Needleman sounds eerily familiar. NeedleMAN – Michael MANN – there’s gotta be a connection.

  3. Anyone who understood Needleman’s research back then questioned his methods and conclusions.

    I grew up in the 60’s and 70’s (born 1956). According to Needleman’s research, me and my cohort should all be severely intellectually dysfunctional due to our elevated lead levels due to exposure to lead paint and lead emissions from tetraethyl lead added to gasoline.

    If a child presented themselves today with blood Pb levels that were average in the 60’s-70’s they would be immediately hospitalized.

    While I do not endorse exposures to any of the heavy metals, you have to try to understand the continuum of effects.

    As a man wiser than I once told me, “Just because the exposure limit is 5 ppm and you are at 4 ppm doesn’t mean that you are safe, and it doesn’t mean that at 6 ppm you are going to die.”

  4. Exposure to lead through water depends on pH. If you drink neutral or alkaline water from a lead cup, you get zero lead in your blood. If you eat salad with a vinegar dressing from a lead bowl, you will certainly pick up some lead. That is not to say it will kill you or lower your IQ, but you will pick some up in detectable amounts.

    Outside this hypothetical case, salad bowls are often made of glazed ceramic, with several common enamels (mostly brightly-colored ones) containing toxic metals that will readily leach in acid.

    Communal drinking water in most places is unpleasantly alkaline, so it almost never is the primary source of rare elements.

  5. where i live the waterworks date from 1845 and are obviously all lead. Since it’s a roman times/medieval mountain village the old part of town the pipes can’t be replaced since the often only a yard wide original footpaths which cover them aren’t allowed to be destroyed. My lead pipe i can see sitting attached to the wall of house.
    Such villages abound in the greater area. Yet no difference in child development clustering exists in the old centers as opposed to the newer pvc piping outer area’s.
    We’re talking here easily of a total population in those area’s in >500.000

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