Autism Linked to Pesticide Exposure

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If autism is associated with exposure to agriultural pesticides a mile away, what effect are the pesticides people use in their homes, work places, shopping areas having? It would be hard to detect because they are so ubiquitous. Even if you avoid using them yourself, they can be in your home from previous occupants, and your next door neighbors probably use them on their yards.

http://www.loe.org/shows/segments.html?programID=14-P13-00026&segmentID=4

Air Date: Week of June 27, 2014

Transcript

CURWOOD: A new paper in Environmental Health Perspectives is sounding a note of warning for pregnant women. The research confirms earlier and smaller studies that also found that living close to areas where agricultural pesticides are used is associated with a spike in the risk of their unborn children having developmental delays and autism spectrum disorders. Neurodevelopmental disorder scientists at the UC Davis MIND Institute recruited 970 children from its ongoing studies of autism for this groundbreaking research. Irva Hertz-Picciotto is Professor of Epidemiology at the Institute and a senior author of the paper and joins us now. Welcome to Living on Earth.

HERTZ-PICCIOTTO: Thanks for having me.

CURWOOD: So tell me, just how risky is it for a pregnant woman to live near a place where pesticides are being sprayed agriculturally?

HERTZ-PICCIOTTO: So in our study, women, who live two-thirds to a mile away from where agricultural pesticides were being applied, had about a sixty-percent higher risk of their child developing an autism spectrum disorder. So the background risk, based on the latest figures from the Centers for Disease Control, is about one in sixty-eight—so, if it’s sixty-percent higher, maybe one in forty-something, which certainly is reason to be concerned.

CURWOOD: And sixty-percent is the average. In certain cases, the risk is much higher, you found.

HERTZ-PICCIOTTO: So there are of course multiple types of pesticides that are used in agriculture, depending on the crops. One of them is called organophosphates—one the most widely used individual pesticides in that class is chlorpyrifos, and that one actually was associated with a particularly high-risk for third trimester and second-trimester use of that product.

CURWOOD: You say high-risk? What do you mean?

HERTZ-PICCIOTTO: Between two- and three-fold higher. That class of pesticides is no longer permitted for use in household products. So, up until about 2000, that was actually one of the main ingredients in our sprays that we used for cockroaches and ants and those sorts of pests around the home. They continue to be used for commercial uses, including in agriculture.

CURWOOD: What are the other chemicals that you studied?

HERTZ-PICCIOTTO: Pyrethroids, which are used not only in agriculture, but also in the household products—they've replaced the organophosphates. They confer about an eighty-percent higher risk for women and their child. These are a product that is labeled usually as ‘natural’ and that's because the original pyrethrin came from the chrysanthemum plant; however, the pyrethroids have been synthesized to be more toxic and to last longer. Some of them can last, you know, maybe a few weeks, others longer than a year.

CURWOOD: And the other chemical group?

HERTZ-PICCIOTTO: The carbamates. They’re somewhat similar in chemical structure to the organophosphates. And they were not associated with a higher risk of autism spectrum disorder, but they were associated with a higher risk for other types of developmental delay, such as intellectual disability or sometimes called cognitive impairment.

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We also need to look at other sources of pesticide exposure, so living near agricultural fields is one, home applications would be an another, and then the third would be residues on food that was sprayed, you know, while it was out in the fields and may still be there when it gets into your home.