Autism Risk Higher Near Pesticide-Treated Fields

Another interesting epidemiological study about the link between pesticide exposure in pregnancy and developmental delays - not just autism. -JR

Autism Risk Higher Near Pesticide-Treated Fields

Babies whose moms lived within a mile of crops treated with widely used pesticides were more likely to develop autism, according to new research 

Jun 23, 2014 |By Lindsey Konkel and Environmental Health News 

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....Babies whose moms lived within a mile of crops treated with widely used pesticides were more likely to develop autism, according to new research. 

The study of 970 children, born in farm-rich areas of Northern California, is part of the largest project to date that is exploring links between autism and environmental exposures.

The University of California, Davis research – which used women’s addresses to determine their proximity to insecticide-treated fields – is the third project to link prenatal pesticide exposures to autism and related disorders.

“The weight of evidence is beginning to suggest that mothers’ exposures during pregnancy may play a role in the development of autism spectrum disorders,” said Kim Harley, an environmental health researcher at the University of California, Berkeley who was not involved in the new study.

 

When women in the second trimester lived near fields treated with chlorpyrifos – the most commonly applied organophosphate pesticide – their children were 3.3 times more likely to have autism, according to the study. 
Credit: Wonderlane via Flickr

One in every 68 U.S. children has been identified with an autism spectrum disorder—a group of neurodevelopmental disorders characterized by difficulties with social interactions, according to the Centers for Disease Control and Prevention.

“This study does not show that pesticides are likely to cause autism, though it suggests that exposure to farming chemicals during pregnancy is probably not a good thing,” said Dr. Bennett Leventhal, a child psychiatrist at University of California, San Francisco who studies autistic children. He did not participate in the new study.....

The biggest known contributor to autism risk is having a family member with it. Siblings of a child with autism are 35 times more likely to develop it than those without an autistic brother or sister, according to the National Institutes of Health.

By comparison, in the new study, children with mothers who lived less than one mile from fields treated with organophosphate pesticides during pregnancy were about 60 percent more likely to have autism than children whose mothers did not live close to treated fields. Most of the women lived in the Sacramento Valley.

The study also reported an increased risk of developmental delays, but not autism, in kids whose moms lived near fields where carbamates, including methomyl and Sevin, were applied.

The researchers said that pesticides could impair brain development and signaling in a way that affects social interactions, learning and behavior.

Previous studies have also linked pesticide use in California to autism spectrum disorders.

In 2007, Harley and her colleagues found a two-fold increase in pervasive developmental disorders (the larger group to which autism belongs) among 531 children in California’s Salinas Valley whose mothers’ urine had higher levels of organophosphate pesticides.

Another study from 2007 found that mothers who lived near fields with the highest applications of two now-banned pesticides – endosulfan and dicofol – were six times more likely to have kids with autism spectrum disorders.

Neurobehavioral effects of developmental toxicity - What's in your garden?

Lancet Neurol. 2014 Mar;13(3):330-8. doi: 10.1016/S1474-4422(13)70278-3. Epub 2014 Feb 17.

Neurobehavioural effects of developmental toxicity.

Grandjean P1, Landrigan PJ2.

Author information

Industrial chemicals known to be toxic to the human nervous system in 2006 and 2013, according to chemical group  

	Number known in 2006	Number known in 2013	Identified since 2006
Metals and inorganic compounds	25	26	Hydrogen phosphide82
Organic solvents	39*	40	Ethyl chloride83
Pesticides	92	101	Acetamiprid,84 amitraz,85 avermectin,86 emamectin,87 fipronil (Termidor),88 glyphosate,89 hexaconazole,90 imidacloprid,91tetramethylenedisulfotetramine92
Other organic compounds	46	47	1,3-butadiene93
Total	202*	214	12 new substances

Industrial chemicals known to cause developmental neurotoxicity in human beings in 2006 and 2013, according to chemical group

	Known in 2006	Newly identified
Metals and inorganic compounds	Arsenic and arsenic compounds, lead, and methylmercury	Fluoride and manganese
Organic solvents	(Ethanol) toluene	Tetrachloroethylene
Pesticides	None	Chlorpyrifos and DDT/DDE
Other organic compounds	Polychlorinated biphenyls	Brominated diphenyl ethers
Total	6*	6

DDT=dichlorodiphenyltrichloroethane. DDE=dichlorodiphenyldichloroethylene.

*

Including ethanol.

Panel. 

Recommendations for an international clearinghouse on neurotoxicity

The main purpose of this agency would be to promote optimum brain health, not just avoidance of neurological disease, by inspiring, facilitating, and coordinating research and public policies that aim to protect brain development during the most sensitive life stages. The main efforts would aim to:

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Screen industrial chemicals present in human exposures for neurotoxic effects so that hazardous substances can be identified for tighter control

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Stimulate and coordinate new research to understand how toxic chemicals interfere with brain development and how best to prevent long-term dysfunctions and deficits

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Function as a clearinghouse for research data and strategies by gathering and assessing documentation about brain toxicity and stimulating international collaboration on research and prevention

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Promote policy development aimed at protecting vulnerable populations against chemicals that are toxic to the brain without needing unrealistic amounts of scientific proof

Abstract

Neurodevelopmental disabilities, including autism, attention-deficit hyperactivity disorder, dyslexia, and other cognitive impairments, affect millions of children worldwide, and some diagnoses seem to be increasing in frequency. Industrial chemicals that injure the developing brain are among the known causes for this rise in prevalence. In 2006, we did a systematic review and identified five industrial chemicals as developmental neurotoxicants: lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene. Since 2006, epidemiological studies have documented six additional developmental neurotoxicants-manganese, fluoride, chlorpyrifos, dichlorodiphenyltrichloroethane, tetrachloroethylene, and the polybrominated diphenyl ethers. We postulate that even more neurotoxicants remain undiscovered. To control the pandemic of developmental neurotoxicity, we propose a global prevention strategy. Untested chemicals should not be presumed to be safe to brain development, and chemicals in existing use and all new chemicals must therefore be tested for developmental neurotoxicity. To coordinate these efforts and to accelerate translation of science into prevention, we propose the urgent formation of a new international clearinghouse.