Pesticides Could Affect Babies' IQs Later On, Study Shows
The Los Angeles Times reports researchers in three separate studies have found expectant mothers exposed to low doses of a specific class of pesticides may have babies who develop slightly lower IQs in later childhood.
Researchers claim children often had lower IQs by age 7 if their mothers had higher-than-average exposure during pregnancy to organophosphates -- pesticides farmers sometimes spray on fruits and vegetables.
Most of the time, those in the study were low-income African-American and Hispanic women.
Researchers in each study measured organophosphates in the mother's urine or blood during pregnancy. Women could have been exposed to pesticides by eating or breathing.
The pesticides were once common in households before the Environmental Protection Agency banned their use in 2002, according to the Times. But, until recently, the chemicals were still common in inner cities as insecticides.
In one study, the newspaper reports, Columbia University researchers found African-American and Dominican women in New York City had the highest levels of chlorpyrifos, a type of organophosphate, in their umbilical-cord plasma.
In another study, researchers from Mount Sinai found Hispanic and African-American women in New York with the highest levels of organophosphates in their urine had children with slightly lower IQs.
Finally, University of California at Berkeley researchers studied Mexican women in Salinas, Calif. They found a seven point IQ difference between children whose mothers had the highest exposure compared with those who had the lowest.
Many of the women were poor, the Times reports, and socioeconomic status is linked to lower IQs.
Researchers in some of the studies reportedly controlled for variables such as income. Women were compared with other women in the data set, not a national average.
"These studies present compelling evidence of the potential effects on children's neurodevelopment from exposure to chlorpyrifos and other organophosphate insecticides," Rudy Rull, a research scientist at the Cancer Prevention Institute of California in Fremont, tells the Times.
However, Brenda Eskenazi, a lead author on the Berkeley study, tells the Times the IQ differences were small, and some only appeared by looking at the data in a certain way. She urges caution.
"My feeling is, we don't have a super-good measurement of organophosphates during pregnancy, especially when there are lot of different ones they are exposed to," she tells the Times. "It's enough to say, there are definitely limitations to the measurement, and I think that's the reason why given that epidemiology is imperfect, you want to see convergence of findings and consistency among what you see in animals and humans."
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