McFarland · Proceedings of the National Academy of Sciences of the United States of America 2022 · Demographic and epidemiological modeling study · n=?

Half of US population exposed to adverse lead levels in early childhood.

Cited 159 times in the scientific literature.

Level 4 - case-series / case-control

Population-level demographic and epidemiological modeling study (grade by design analogy)

PubMed 35254913 · doi:10.1073/pnas.2118631119 · record verified 2026-08-28

What was done

Demographic and epidemiological modeling was used to estimate historical early childhood lead exposure among the living US population and project its cumulative cognitive impact as of 2015. Specific data sources and modeling methods are not described in the abstract.

What was found

An estimated >170 million Americans alive in 2015 experienced high lead exposure during early childhood, with several million exposed to five or more times the current reference level. Lead exposure was estimated to be responsible for a cumulative population-level loss of 824,097,690 IQ points.

Why it matters

This study highlights the substantial, enduring public health and cognitive burden carried by living US adults who experienced high early childhood lead exposures prior to regulatory bans.

Limits

The findings rely on macro-level modeling rather than direct longitudinal individual measurements. Specific modeling assumptions, data sources, confidence intervals, and other non-cognitive health outcomes are not detailed in the abstract.

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