Reporting their findings in the journal Pediatrics, researchers at Columbia University say that common household pyrethroid insecticides may be causing the delayed mental development of young children.
When the EPA phased out the widespread residential use of chlorpyrifos and other organophosphorus insecticides in 2000, they were replaced with pyrethroid insecticides. But the safety of these replacement insecticides remained unclear, as they had never been evaluated for long-term neurotoxic effects after low-level exposure.
Now, in the first study to examine the effects of these compounds on the developing fetal brain, scientists at Columbia University's Mailman School of Public Health have found a significant association between piperonyl butoxide (PBO), a common additive in pyrethroid formulations, and delayed mental development at 36 months.
The insecticide permethrin was selected for the evaluation because it is one of the most common pyrethroid insecticides used in U.S. homes, as well as the most commonly sold pesticide. PBO, a chemical that is added to insecticides to increase efficacy was also selected for evaluation.
In all, 342 women were studied for permethrin exposure in personal air during pregnancy. The children of these mothers were evaluated for cognitive and motor development at age three.
PBO was detected in the majority (75 percent) of personal air samples. The study noted that children who were more highly exposed to PBO scored 3.9 points lower on the Mental Developmental Index than those with lower exposures.
"This drop in IQ points is similar to that observed in response to lead exposure," said researcher Megan Horton. "While perhaps not impacting an individual's overall function, it is educationally meaningful and could shift the distribution of children in the society who would be in need of early intervention services. With the exception of the increased odds of motor delay in the lowest PBO exposure group, prenatal exposure to PBO seems to have an impact on cognitive rather than motor development, which is quite worrisome because mental development scores are more predictive of school readiness."
Mother's exposure to air pollutants can affect child's IQ
Eating licorice may affect offspring's IQ
Boosting Baby's Brain With Omega-3
Link Found Between Childhood Lead Exposure And Criminality
Source: Columbia University's Mailman School of Public Health