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Autism Linked to Maternal Exposure to Pesticides

by aseligmann — last modified Jul 11, 2010 12:00 AM

A new study on children born in California's Central Valley suggests that autism in those children might be linked to prenatal exposure to two insecticides used on fields near their mothers' homes.

Autism Linked to Maternal Exposure to Pesticides

A new study on children born in California's Central Valley suggests that autism in those children might be linked to prenatal exposure to two insecticides used on fields near their mothers' homes.

Cases of autism and related disorders were associated with maternal exposure to applications of dicofol and endosulfan during early pregnancy. The rate of autism increased as amounts of these pesticides increased. Distance of the mother's residence was also a factor, with cases of autism decreasing the farther away from the fields that she lived.

Children were six times more likely to have been diagnosed with autism if their mothers had spent early pregnancy in homes within 500 meters (547 yards) of fields with the highest levels of dicofol and endosulfan applications when compared to a group whose mothers did not live near agricultural fields.

Autism is characterized as a neurodevelopmental disorder. California researchers wanted to test the idea that pesticide exposure from living near agricultural fields during pregnancy might contribute to problems with fetal development of the nervous system. They conducted this exploratory study using information gleaned from several state databases, focusing on children born in the Central Valley, an agricultural region. After identifying children who had been diagnosed with autism, they matched the mothers' addresses to agricultural activity in the area. They then honed in on specific pesticides that had been used nearby during the mother's first eight weeks of pregnancy. For comparison, they used information about children born in this region who had not been identified as autistic.

It would not have seemed surprising if organophosphate insecticides had been associated with cases of autism, since organophosphates are well known for their toxicity to the nervous system. But in this study, only dicofol and endosulfan, which belong to the organochlorine* chemical family, were linked to cases of autism. Researchers cautioned that this connection needed further study.

*DDT, chlordane and other organochlorine insecticides have been banned in the United States. Since the EPA issued cancellation orders for lindane in 2006, dicofol and endosulfan are the only remaining organochlorines registered for pesticide use. The FDA still permits the use of lindane for treatment of head lice.


NEWS STORY:

Pesticide link to autism suspected: A state study suggests two farm sprays may raise the changes of having a child with the disorder.
Marla Cone. Los Angeles Times. July 30, 2007
Abstract with link to complete article: http://www.freewebs.com/calnaa/research.htm

STUDY SOURCE:

Maternal residence near agricultural pesticide applications and autism spectrum disorders among children in the California Central Valley.
Roberts, EM et al. 2007.
Environmental Health Perspectives. 115(10):1482-1489
http://www.ehponline.org/docs/2007/10168/abstract.html