| First Human Study to Show Benefits to Newborns
from Federal Ban on Home Use of Two Insecticides
A federal ban on two insecticides has resulted in a significant
reduction in their impact on newborns' birth weight and length,
according to a new study funded by the National Institute of Environmental
Health Sciences of the National Institutes of Health, the U.S. Environmental
Protection Agency, and other private foundations.
The results of the study the first one to demonstrate the
benefits of the ban during pregnancy in human subjects will
be published in Environmental Health Perspectives, the monthly
peer-reviewed journal of the NIEHS. It is now available online at
The study, released by the Columbia Center for Children's Environmental
Health, part of the Mailman School of Public Health at Columbia
University, measured the impact on fetal growth of two insecticides
chlorpyrifos and diazinon whose use in households was
banned by the federal government starting in 2000. The insecticides
had been among the most commonly-used agents for residential pest
In the study, researchers measured the levels of the two insecticides
in blood drawn from the umbilical cords after delivery, both before
and after the ban, and correlated those levels with the babies'
birth weight and length. All blood samples were frozen and stored
at -70 degrees Centigrade in order to ensure the stability of the
pesticides. Subsequent analyses were performed on frozen samples
at three different times spring 2001, summer 2002 and
They found that prior to January 2001, newborns with combined insecticide
exposures in the highest 26th percentile had birth weights averaging
almost 200 grams (almost half a pound) less than infants with no
detectable pesticide levels. The researchers also noted a highly
significant inverse association between the combined exposures and
newborn birth length. However, when they looked at the relationship
between insecticide exposures and fetal growth after January 2001,
the exposure levels had been reduced substantially, and the impact
on weight and length was no longer apparent.
"This human study confirms the developmental impact, shown
previously in animal studies, of these insecticides," said
Dr. Robin M. Whyatt, an Assistant Professor at the Mailman School
and principal author of the study. "It also demonstrates the
positive effect of the federal ban, which has substantially reduced
exposures and benefitted human health."
"The differences in fetal growth seen here are comparable
to the differences between babies whose mothers smoke during pregnancy
and babies whose mothers don't," said Whyatt. "The fact
that the ban was associated with such an immediate change in birth
weight and length provides considerable evidence of cause and effect."
According to the study investigators, the widespread use of the
two pesticides makes them good candidates for a residential study
of this kind. Chlorpyrifos, for instance, was the most frequently
used residential insecticide in New York City prior to the ban.
Both compounds are still widely used in agriculture and continue
to be found in the food supply.
"This study is good news for our nation's children,"
said Dr. Frederica P. Perera, Director of the Center and the study
team leader. "The evidence that birth weight increased following
the Environmental Protection Agency's regulatory action implies
important benefits for the children's future health and development.
At the same time, the results highlight the need to address continuing
prenatal exposures to these and other toxic pesticides."
The study is part of a broader, multi-year research project, "The
Mothers & Children Study In New York City," started in
1998, which examines the health effects of exposure of pregnant
women and babies to air pollutants from vehicle exhaust, the commercial
burning of fuels, and tobacco smoking, as well as from residential
use of pesticides and allergens. The present study included a sample
of 314 infants of African American and Dominican women in Washington
Heights, Central Harlem and the South Bronx.
Other co-authors of this study include Dr. Virginia Rauh from the
Columbia Center, Dr. Dana Barr from the Centers for Disease Control
and Prevention, and David Camann from Southwest Research Institute.
For more information or a copy of the study, please contact Heather
Ross at 212-576-2700, extension 243.