Prenatal exposure to a
chemical designed to enhance the effect of household
insecticides may harm neurodevelopment , data from a
prospective cohort study of children found.
Data analyzed for almost 350 children found that each unit
increase in exposure to piperonyl butoxide — a chemical
found in fogger type products to kill flying insects or fleas —
was associated with a small but statistically significant
increase in the risk of delayed mental development at age
three, according to Dr. Megan Horton, of Columbia's
Mailman School of Public Health in New York City, and
colleagues.
But the risk increased with exposure and most highly
exposed children had a more than threefold increased
likelihood of slowed mental development Horton and co-
authors reported online ahead of the March issue of
Pediatrics .
Piperonyl butoxide a chemical mixed with pyrethroid
pesticides to improve efficacy.
Although the effects associated with exposure were modest,
the researchers wrote, "they were comparable in magnitude
to reports from studies of other prenatal neurotoxicants that
affect development in young children."
They added, however, that "these findings should be
considered preliminary and may be useful for generating
future hypotheses."
The use of residential pesticides has shifted in recent years
from organophosphorus insecticides — which have been
associated with impaired neurodevelopment — to pyrethroid
insecticides, which have not been evaluated extensively for
potential developmental toxicity.
There is concern because piperonyl butoxide is known to
block the body’s ability to breakdown pyrethroid
insecticides into harmless — detoxified — waste.
Exposure to piperonyl butoxide has also been shown to
generate reactive oxygen species, lending support to the
possibility that oxidative damage could be a mechanism for
altered neurologic development.
In the current study, Horton and her colleagues assessed
exposure to piperonyl butoxide in personal air collected
during the pregnancies of 348 black and Dominican mothers
and to the common pyrethroid pesticide, permethrin, in
personal air and maternal and umbilical cord plasma.
The mothers, from low-income neighborhoods in New York
City, were participating in the Columbia Center for
Children's Environmental Health (CCCEH) Mothers and
Newborns cohort.
The researchers assessed the cognitive and motor
development of the offspring at age 3 years using the
Bayley Scales of Infant Development.
"This finding is worrisome because mental development
index scores are more predictive of school readiness,"
Horton and her colleagues wrote.
Horton and her team acknowledged that their study was
limited by possible residual confounding from unmeasured
factors and by the lack of measurement of piperonyl
butoxide exposure in blood or urine samples.
The study was supported by the National Institute of
Environmental Health Sciences, Environmental Protection
Agency, Educational Foundation of America, John and
Wendy Neu Family Foundation, New York Community Trust,
and Trustees of the Blanchette Hooker Rockefeller Fund.
The authors reported that they had no conflicts of interest.