Childhood lead exposure leads to structural changes in middl
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More than three decades after they were found to have elevated blood lead levels as children, a group of middle-aged adults were found to have some small but significant changes in brain structure that corresponded to their dose of lead exposure in early life.

MRI scans at age 45 revealed some small but significant changes in the brains of the people who had higher lead exposures measured at age 11.

For each 5 micrograms per deciliter more lead they carried as children, the study participants lost an average of 2 IQ points by age 45. They also had slightly more than 1 square centimeter less cortical surface area and 0.1 cubic centimeter less volume in the hippocampus, which plays a role in memory, learning and emotions.

Participants with the highest childhood lead exposures also demonstrated structural deficits in the integrity of their brains' white matter, which is responsible for communication between brain regions.

The research participants themselves reported no loss of cognitive abilities, but people close to them said otherwise, noting that they tended to display small everyday problems with memory and attention, such as getting distracted or misplacing items.

"We find that there are deficits and differences in the overall structure of the brain that are apparent decades after exposure," said first author on the study, which appears in the Journal of the American Medical Association. "And that's important because it helps us understand that people don't seem to recover fully from childhood lead exposure and may, in fact, experience greater problems over time."

The findings come from a long-term study of more than 1,000 people born in the same town. For this study, the researchers had childhood lead exposure data for 564 of the study participants, who grew up during the peak era of leaded gasoline, which ran from the late-1960's to the late-1980s. As was true across the developed world during that time, almost all of the study participants were exposed to higher lead levels than are permitted today.

"These findings involve gross features of how your brain looks as a whole," explained senior author. "This research started by looking at these features of the brain because scientists don't really know a whole lot about childhood lead exposure and the brain later in life."

But the differences are there. He said they may reflect long-term consequences of lead exposure, since the cortical surface area, hippocampal volume and white matter structure all grow during childhood and peak in early adulthood.

Source: https://jamanetwork.com/journals/jama/article-abstract/2772961
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