Summary: New research shows that prenatal lead exposure can have measurable effects on cognitive performance more than six decades later. A study linking lead levels measured in baby teeth to cognitive test scores at age 60+ found especially strong associations for women, with second-trimester exposure tied to declines comparable to several years of additional brain aging.
Researchers analyzed a rare archive of baby teeth donated in the St. Louis area between 1958 and 1972 to estimate prenatal and early-life lead exposure. Those historic exposure measures were then compared with contemporary assessments of thinking and memory skills collected from the same individuals about 60 years later. The study reported that higher lead concentrations during the second trimester were associated with lower cognitive test scores in late adulthood, particularly among female participants.
Key findings
- Biological archive: Baby teeth record lead uptake as they develop in the womb and in early childhood, allowing precise retrospective measurement of prenatal exposure.
- Long-term association: Lead exposure during the second trimester was linked with reduced performance on tests of thinking and memory roughly 60 years later.
- Sex-specific effect: The association was strongest and statistically significant in women.
- Magnitude of effect: In women, each 1 part per million (ppm) increase in second-trimester tooth lead concentration corresponded to a decrease of 0.16 standard deviations on the cognitive tests — an effect the authors equated to about three years of additional cognitive aging in their sample.
- Contemporary relevance: While lead use in the United States peaked decades ago, recent contamination events demonstrate that lead exposure remains a public health concern.
Source: AAN
Study overview
The research, published February 18, 2026, in the journal Neurology, does not establish causation but documents a robust association between prenatal lead exposure and later-life cognitive performance. The lead measurements came from baby teeth collected from children born between 1958 and 1972. Parents originally donated those teeth for a radiation study; decades later, investigators were able to re-contact many of the donors and invite them to complete at-home cognitive testing.
From the original collection, researchers located 715 individuals who completed the cognitive assessments and whose baby teeth were still available for laboratory analysis. The average age of participants at testing was 62, and the median tooth lead concentration across the group was 1.34 parts per million. The analysis focused on trimester-specific lead levels because tooth formation follows a timeline that can distinguish exposure windows during pregnancy and early life.
After adjusting for potential confounding factors such as parental education and childhood socioeconomic conditions, the investigators found that second-trimester lead concentrations were particularly predictive of lower thinking and memory test scores in women. The team reported that every additional 1 ppm of lead measured in the tooth tissue formed during the second trimester was associated with cognitive test performance lower by 0.16 standard deviations — an effect size the authors contextualized as comparable to three years of cognitive aging within their dataset.
Interpretation and limitations
The study highlights the potential for prenatal environmental exposures to influence brain health decades later. However, it is important to note the results show association rather than direct causation. The sample had limited diversity: most participants were White and had relatively high education and socioeconomic status in childhood. Because of this demographic profile, the findings may not be generalizable to all populations or to groups with different lifetime exposures and health determinants.
The authors and editorialists emphasize that, despite reductions in lead use over recent decades, lead contamination events — such as those affecting drinking water or consumer products — demonstrate that exposure risks persist. Continued surveillance, prevention, and research into how early-life exposures shape cognitive aging remain public health priorities.
Funding: The study was supported by the National Institutes of Health and the National Institute of Environmental Health Sciences.
Key questions answered
A: Scientists analyzed a unique collection of baby teeth donated by parents in the late 1950s and 1960s. Because teeth form in layers during fetal development and early childhood, they capture and preserve lead exposure that occurred before birth and in infancy, creating a reliable retrospective record.
A: No. The study reports an association in a particular sample, not proof that lead exposure is the sole cause of later cognitive changes. Many other factors — education, lifestyle, health conditions, and later-life exposures — influence cognitive aging. The findings do underscore that prenatal environment can be an important, often overlooked factor.
A: The reasons for the sex-specific findings are not yet clear and merit further study. Possible explanations include sex differences in how lead is stored in bone and released across the life course, as well as hormonal and biological differences that influence brain aging. Future research will need to investigate these mechanisms.
Editorial notes
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full for this summary.
- Additional context was provided by the publication’s staff.
About this research news
Author: Renee Tessman
Source: AAN
Contact: Renee Tessman – AAN
Image: The image is credited to Neuroscience News
Original research: The research findings are published in the journal Neurology.