Autism is a neurodevelopmental disorder characterized by impaired verbal and non-verbal communication, weakened social interactions, and limited and repetitive behavior — and it's greatly affecting the Latino community.

According to a recent study from the University of California, pregnant women who live in close proximity to fields and farms that were treated with certain pesticides are more likely to bear a child with an autism spectrum disorder (ASD). Children of migrant workers are likely to be disproportionally affected, as many female migrant workers spend entire seasons farming, harvesting, and managing pesticide-ridden fruits and vegetables. Many Latina mothers also use insecticides in their homes and gardens.

Pesticides affect signaling cells in the nervous system, creating a plausible link between pesticides and the three main types of ASD — Asperger's syndrome, pervasive developmental disorder not otherwise specified (PDD-NOS), and autistic disorder, as well as other developmental delays among children.

The authors of the study indicated that the children of mothers exposed to organophosphates and pyrethroid insecticides were 60 percent more likely to have ASD than children of non-exposed mothers. Researchers mapped and tracked pesticide exposure during the pregnancy of 970 mothers, which resulted in 486 children with an ASD, 168 children with a developmental delay and 316 children with typical development.

"Ours is the third study to specifically link autism spectrum disorders to pesticide exposure, whereas more papers have demonstrated links with developmental delay," said lead author Janie F. Shelton, from the University of California, Davis.

One third of the mothers involved in the study lived within a mile of fields treated with pesticides. For certain pesticides, exposure prior to conception and in the third trimester were detrimental, while other pesticides didn't discrimination regarding exposure and pregnancy. Carbamate pesticides were not linked to ASDs, but were linked to developmental delays.

Dr. Philip J. Landrigan, who directs the Children's Environmental Health Center at the Icahn School of Medicine at Mount Sinai in New York and was not affiliated study, openly speculated that pesticides likely drift from crops, contaminating the air, and leave pregnant women exposed to the neurologically damaging pesticides, though the study did not measure airborne pesticide levels.

"We already knew from animal studies as well as from epidemiologic studies of women and children that prenatal exposure [to pesticides] is associated with lower IQ," Landrigan told Reuters Health. "This study builds on that, uses the population of a whole state, looks at multiple different pesticides and finds a pattern of wide association between pesticide exposure and developmental disability."

Exposure is difficult to avoid in certain parts of California; the state produces more agricultural products than any other in the nation, and statewide, approximately 200 million pounds of active pesticide are used each year. Because of this, children born in California are several times more likely to be diagnosed with autism than a child born in, say, Delaware.

"Multiple studies have shown that black and Latino children are underidentified, diagnosed later and, once diagnosed, receive poorer quality of care," said Autism Speaks Vice President for Community Affairs Jamitha Fields. "Autism Speaks' Early Access to Care initiative seeks to increase access to high-quality early intervention for all children on the autism spectrum."

Shelton said they still must investigate whether "certain sub-groups are more vulnerable to exposures to these compounds than others." That said, 39 percent of California's population is Latino, 71 percent of farmworkers are Latino (22 percent female), and autism clusters have been identified in 10 of California's major cities, many of which which are heavily populated with Latinos. Another report indicated that Central and South American-born Hispanics are among those most likely to have children born with ASD, crediting a "complex combination of genetic and environmental risk factors."

Of course, there is a complex array of factors that can influence autism rates, contributing to the fact that 4 percent of U.S. kids must spend extra time reaching social, motor skill and communication milestones, but environmental factors seem to play a large part. There are a number of triggers, risk factors, and issues with health care that influence the likelihood of autism. Environmental effects may increase the likelihood of a subset of autism disorders, however many scientist make the point of saying that correlation does not equal causation. Eric Fombonne, a professor at Oregon Health & Science University and an autism researcher who focuses on ASD epidemiology says that it's caused by "gene-gene interactions" and "gene-environment interactions."

Meanwhile parents should limit contact with pesticides, and limit use of pesticides, such as bug spray, within the home, which will likely lessen the increase of the disorder that's greatly affecting the children of foreign-born mothers who are black, Central or South American, Vietnamese or Filipino. More research must be done to gauge causation and manageable treatments for ASDs.

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