Insecticide Linked to Brain Abnormalities in
MONDAY, April 30 (HealthDay News) -- A new, small study links
maternal exposure to a commonly used insecticide to unusual changes
in the brain structures of young children, although the research
doesn't definitely prove that the pesticide is at fault.
The findings raise more questions about the safety of the
insecticide, known as chlorpyrifos, which is used to treat farm
products in the United States but has been almost entirely banned
in homes. The U.S. Environmental Protection Agency says exposure to
the insecticide in children through food is "below the level of
"People should wash their fruits and vegetables very carefully before eating, and pregnant women should not be working in agricultural settings where there might be an occupational exposure," said study lead author Virginia Rauh, deputy director of the Columbia Center for Children's Environmental Health at Columbia University.
Chlorpyrifos is widely used to kill insects on farms. "It is
used on corn, many types of fruits, many types of leafy green
vegetables and cotton," Rauh said. "It's also used for a variety of
other commercial purposes -- as a spray to control pests on golf
courses, road medians, Christmas tree farms and at various other
places." People are often exposed through insecticide residue on
fruits and vegetables, Rauh said.
Previous research has linked indoor residential exposure in
pregnant mothers to lower birth weights. "We found evidence that
there was poorer cognitive [mental] development and potentially
more behavior problems in kids who were exposed," Rauh said.
In the new study, the researchers used MRI machines to scan the
brains of 40 children aged 5 to 11 years. The mothers of 20 of them
had high levels of exposure to the insecticide while they were
pregnant with the children.
The mothers of the other 20 kids had low levels of exposure. The
brains of the kids with high exposure were more likely to have
certain enlarged structures in the brain. They also had thinning in
some parts of the brain.
Rauh acknowledged that the study doesn't prove a direct
cause-and-effect link between the insecticide and the differences
in the brains between the children. One possibility is that the
mothers of the children had different diets or were exposed to
other chemicals in their homes or workplaces, but Rauh said they
share one similarity: Most came from a low-income section of
Manhattan and almost all were poor.
The findings are worrisome because the differences in brain
structure appear to be harmful, she said. "An abnormal enlargement
would not necessarily be a good thing."
In addition, there are links between the sizes of parts of the
brain and problems with behavior and thinking, she said.
At the moment, Rauh said, she and her colleagues are studying
whether they can link exposure to the insecticide to long-lasting
changes in behavior in kids at ages 9 and 10.
Dr. Bruce Lanphear, a professor of health sciences who studies
environmental risks at Simon Fraser University in Vancouver,
British Columbia, praised the study but acknowledged it doesn't
prove the insecticide is harmful. However, he said, "even though
this paper is not the final word, it builds on existing studies
that basically say [author] Rachel Carson was right: Widespread
exposure to toxins is likely to cause fairly severe disease."
He asked: "Are we willing to sacrifice our children's brains for
profits? That's the choice we're making, whether we know it or
Study lead author Rauh said one way to avoid pesticides is to
eat organic food, but it's expensive. It's smart to wash produce
carefully, she said, and use less-toxic ways to control pests
around the house, such as bait traps.
Stephanie Engel, an associate professor of epidemiology at the
University of North Carolina at Chapel Hill, put it this way: "The
general lesson here is that the dangers that chemicals pose to
child development are not always understood. These children were
exposed during a period when chlorpyrifos was deemed safe for
residential use. So it just makes good sense for pregnant women to
be cautious about the chemicals they use during pregnancy. Even
ones that we are told are 'safe' may later turn out to be
The study appears online April 30 in the
Proceedings of the National Academy of Sciences.
For more about the insecticide chlorpyrifos, try the
U.S. Environmental Protection Agency.
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