Summary: The consequences of lead exposure may take six decades to fully manifest. A remarkable study has linked lead exposure during the second trimester of pregnancy to lower cognitive performance in adults 60 years later.
By analyzing a unique collection of baby teeth donated in the St. Louis area between 1958 and 1972, researchers were able to measure prenatal lead levels and compare them with the cognitive scores of those same individuals today. The findings were particularly striking for female participants: every one part per million increase in second-trimester lead was associated with cognitive declines equivalent to three years of additional aging.atal-lead-cognitive-aging-
Key Facts
- The “Tooth Timeline”: Baby teeth act as a biological archive, trapping lead as they form in the womb and early childhood.
- Long-Term Impact: Lead exposure in the second trimester was associated with lower scores on thinking and memory tests six decades later.
- Gender Specificity: The association between prenatal lead and late-life cognitive function was primarily observed in female participants.
- Aging Equivalent: For women, a small increase in lead concentration was linked to a cognitive drop-off equal to three years of natural brain aging.
- Modern Relevance: Although lead use in the U.S. peaked decades ago, current events—like the Flint water crisis and recent lead-contaminated food recalls—highlight that lead remains a critical public health threat.
Source: AAN
Exposure to lead before birth is associated with lower performance 60 years later on tests of thinking and memory skills in female participants, according to a study published on February 18, 2026, in Neurology.
The study does not prove that lead exposure is the cause of the lower scores on tests of thinking and memory skills; it only shows an association.
“Lead exposure in the United States peaked during the 1960s, ’70s and ’80s, and children born during those years are now entering midlife and older adulthood, when these early-life exposures could have long-term effects on their cognitive health,” said study author Ruby C. Hickman, PhD, who conducted the research while at Harvard T.H. Chan School of Public Health in Boston, Massachusetts.
Researchers tested lead levels in an unusual way. For a study of radiation exposure, parents in the St. Louis, Missouri, area donated their children’s baby teeth from 1958 to 1972. The study team at Harvard Chan School worked to track down these children six decades later and asked them to take cognitive tests on their home computers or devices.
Researchers still had the baby teeth and tested them for lead levels. Because teeth pick up lead as they are forming, baby teeth can show what levels of lead someone was exposed to before they were born and in early life.
A total of 715 people with an average age of 62 were located, took the tests and had their baby teeth analyzed for lead.
Participants had a median tooth lead concentration of 1.34 parts per million.
For female participants, each one part per million higher concentration of lead during the second trimester was associated with test scores that were lower by 0.16 of a standard deviation, which was the equivalent of three years of aging in their data.
These results took into account other factors that could affect test scores, such as parents’ education level and their family’s financial status.
“While lead exposure has declined over recent decades, the Flint water crisis and recent lead contamination in cinnamon applesauce marketed to young children are examples of ongoing exposure problems in the United States, and lead exposure remains an issue globally as well,” Hickman said.
A limitation of the study is that participants were mainly white people with high levels of education and higher socioeconomic level as children, so the results may not apply to other groups.
Funding: The study was supported by the National Institutes of Health and National Institute of Environmental Health Sciences.
Key Questions Answered:
A: Scientists used a rare collection of “baby teeth” donated by parents in the 1950s and 60s for a radiation study. Because teeth lock in lead as they develop, they provide a perfect “time capsule” of exactly what a person was exposed to while still in the womb.
A: Not necessarily. The study shows an association, not direct proof of cause and effect. It highlights that early-life environmental factors can be a “hidden” variable in how our brains age, but other factors like education, diet, and lifestyle still play massive roles in cognitive health.
A: This is a key area for future research. It may be linked to how lead is stored in and released from bones during different life stages, such as pregnancy or menopause, which can differ significantly between biological sexes.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neuroscience and cognitive aging research news
Author: Renee Tessman
Source: AAN
Contact: Renee Tessman – AAN
Image: The image is credited to Neuroscience News
Original Research: The findings will appear in Neurology
