Childhood lead exposure causes permanent brain damage
December 4th 2009 22:40
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By Robert Priedt, HealthDay USA Today
Childhood exposure to lead can cause permanent brain damage, a new study has found.
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The study included 33 adults, mean age 21, who were enrolled as infants in the long-term Cincinnati Lead Study, which looked at prenatal and early childhood exposure in 376 infants from high-risk areas of Cincinnati between 1979 and 1987.
The study participants had blood lead levels ranging from 5 micrograms to 37 micrograms per deciliter, with a mean of 14. They had IQ deficiencies and histories of juvenile delinquency and criminal arrests.
Functional MRI was used to monitor the participants' brains while they did two tasks that assess attention, decision making and impulse control. The scans showed that in order to complete a task that required inhibition, participants with elevated blood lead levels required activation from additional regions within the brain's frontal and parietal lobes.
"This tells us that the area of the brain responsible for inhibition is damaged by lead exposure and that other regions of the brain must compensate in order for an individual to perform. However, the compensation is not sufficient," Cecil said.
According to Cecil, the brain's white matter, which organizes and matures at an early age, adapts to lead exposure. But the frontal lobe, which is the last to develop, suffers permanent damage from lead exposure as it matures.
"Many people think that once lead blood levels decrease, the effects should be reversible, but, in fact, lead exposure has harmful and lasting effects," Cecil said.
The study was scheduled to be presented Tuesday at the Radiological Society of North America annual meeting, in Chicago.
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