Why Lead May Impair the Cognitive Function of Boys More Than Girls

Lead isn't good for anyone's health, but it may actually be harder on boys and girls. Scientists have found that the female hormones estrogen and estradiol may help ward off the effects of lead exposure for young boys, which may explain why greater numbers of boys than girls suffer from cognitive disabilities linked to lead.

The researchers tested executive function and reading readiness skills in 40 young children between the ages of three to six. These children lived within the Environmental Protection Agency-designated Omaha Lead Superfund site, which is the largest residential lead clean-up area in the nation. This region had significant lead contamination in surface soils due to emissions of a lead refinery that operated in the area for 125 years. In addition, many old homes in the area contained lead-based paint.

Of all of the children studied, 23 had elevated blood lead levels and 17 did not. While boys with these elevated lead levels tested poorly on executive function, though, girls with elevated levels had test results that were much less pronounced.

"The study supports existing research suggesting that estrogen and estradiol in females may act as neuroprotectants against the negative impacts of neurotoxins," said Maya Khanna, one of the researchers, in a news release. "The findings also add to the evidence that lead exposure has a negative impact on cognitive functioning, especially those functions housed within frontal areas of the brain. Executive functions are controlled largely by the prefrontal cortex, while reading skills rely more heavily on the temporal or parietal areas of the cerebral cortex."

The findings are published in the Journal of Environmental Health.

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