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Your Environment. Your Health.

Phthalate Exposure Linked to Lower IQ

Frederica Perera, Ph.D., Dr.P.H.; Robin Whyatt, Dr.P.H.
Columbia University Mailman School of Public Health
NIEHS Grants: R01ES013543, R01ES014393, R01ES08977, P01ES009600

NIEHS-funded researchers found that 7-year-olds who experienced prenatal exposure to elevated levels of two phthalates had lower IQ scores than children exposed to lower levels. The new research adds to the group’s earlier findings of associations between prenatal exposure to phthalates and problems with cognitive function and behavior at age 3.

The study included 328 New York City women and their children from the Columbia Center for Children’s Environmental Health longitudinal birth cohort. During the third trimester of pregnancy, the researchers measured urinary metabolites of four phthalates: di-n-butyl phthalate (DnBP), di-isobutyl phthalate (DiBP), di-2-ethylhexyl phthalate, and diethyl phthalate.

At age 7, the children of the mothers with the highest concentrations of DnBP and DiBP metabolites had IQs 6.6 and 7.6 points lower, respectively, than children of mothers exposed to the lowest concentrations. They found no associations between the other two phthalates and child IQ. Other research has shown that a six- or seven-point decline in IQ can substantially affect academic achievement and occupational potential.

Although some phthalates are banned from use in children’s products in the U.S., pregnant women are still exposed to phthalates used in consumer and personal care products.

Citation: Factor-Litvak P, Insel B, Calafat AM, Liu X, Perera F, Rauh VA, Whyatt RM. 2014. Persistent associations between maternal prenatal exposure to phthalates on child IQ at age 7 years. PLoS One 9(12):e114003.

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