Leading the study into pesticide effects on children are (from left) Tom Petros, Ric Ferraro, Sue Offutt, Patricia Moulton, and (not pictured) Sally Pyle. The project is the first in the United States to focus on this population segment.

UND project is among the first to study children and exposure to pesticides

By Jan Orvik

Does exposure to pesticides — even at low levels — affect children’s cognitive development? UND scientists were the first in the United States to study that question. Though there are multiple studies of the effect of pesticides on adults, no such U.S. research exists for school-age children.

Evidence suggests that exposure to large doses of pesticides, such as caused by farm accidents, can carry serious health consequences. However, much less is known about the impact of low-level, long-term exposure. And even less is known about how pesticide exposure affects children. In fact, just one published study exists from Mexico.

“I hope we’ll find that low exposure to pesticides doesn’t affect children,” said Sally Pyle, professor of biology. “But I also feel that we need to understand how what we do affects them. Brain development in children occurs over a much longer period than we previously thought.”

In addition to Pyle, the team includes psychology professors Tom Petros and Ric Ferraro, and Sue Offutt and Patricia Moulton from the Center for Rural Health. They were awarded $100,000 from the National Institutes of Health to study the cognitive effect of pesticides on children. The Centers for Disease Control is providing blood and urine analyses at no cost.

The study took place over the summers of 2004 and 2005, and involved 128 children, ages 7 to 12. Half live on or next to a farm, and the remaining half live at least one mile from a farm. The researchers tested each child’s cognitive, problem-solving, attention, and IQ abilities, and sent urine and blood samples to the Centers for Disease Control to measure pesticide exposure. Parents also took cognitive tests, filled out a 24-hour food intake chart for their children, and answered questions about their use of cleaners and pesticides around the home.

The goal was to investigate exposure and determine if higher pesticide levels affect cognition. Researchers are controlling for variables such as parental IQ, socioeconomic status, and other factors. The eventual goal of this and other research, said Ferraro, is to track pesticide exposure by county, along with the incidence rate of neurological diseases, to determine if a link might exist. He’s spent the last 20 years examining the effects of neurological diseases on cognition and is now extending that work into examination of farmers, pesticides, and neurological diseases. He’s especially interested in those links because today nearly everyone is exposed to pesticides from runoff, in the air, and in residue on food.

The research is unique because of its interdisciplinary nature — the collaboration between psychology, rural health, and biology — and the fact that studying the effect of pesticides on children is virtually unknown.

Most pesticides, said Pyle, work by damaging the nervous system of insects. The problem is that human and insect nervous systems work similarly, and what is toxic to insects is also toxic to humans, albeit at different levels. School-age children are still honing their intellectual ability and comprehension, and the nervous system and brain continue to develop through the teen years. Though it’s difficult to isolate specific chemicals in blood and urine samples, the scientists are also measuring levels of other agents such as the mosquito repellant DEET and the herbicide 2,4-D.

The researchers expected difficulties recruiting subjects, but that wasn’t the case.

“Parents of children in the study told us that they wondered about pesticide exposure,” said Moulton, an assistant professor of rural health. “Rural residents have been supportive. They’re very interested in seeing the results.” Parents will receive the data on pesticide levels in their children as well as the results of the cognition tests. Full findings of the study are expected by summer.
If a correlation is found, Petros said, there are fairly simple mitigation techniques to employ, such as storing exposed clothing separately, better air filtration, and removing shoes before entering the house.

“Pesticides can migrate from shoes onto the carpet, where young children play,” said Moulton. “Education about ways to reduce exposure can help prevent much of the problem.”

“No one has zero-exposure to pesticides,” said Pyle. “And it’s not reasonable to stop using pesticides. Our goal is to figure out what’s happening and help people lower their exposure.