The LA Times reports on a study, published in Environmental Health Perspectives, suggesting a possible causal link between pesticides and autism. The LAT is careful to point out that the study used a small sample size, that the California Department of Public Health which conducted the study is only characterizing the results as preliminary data indicating that there MAY be an association between the pesticides which were the subject of the study and incidents of autism.
Women who live near California farm fields sprayed with organochlorine pesticides may be more likely to give birth to children with autism, according to a study by state health officials to be published today.
The rate of autism among the children of 29 women who lived near the fields was extremely high, suggesting that exposure to the insecticides in the womb might have played a role. The study is the first to report a link between pesticides and the neurological disorder, which affects one in every 150 children.
But the state scientists cautioned that their finding is highly preliminary because of the small number of women and children involved and lack of evidence from other studies.
"We want to emphasize that this is exploratory research," said Dr. Mark Horton, director of the California Department of Public Health. "We have found very preliminary data that there may be an association. We are in no way concluding that there is a causal relationship between pesticide exposure of pregnant women and autism."
The two pesticides implicated are older-generation compounds developed in the 1950s and used to kill mites, primarily on cotton as well as some vegetables and other crops. Their volumes have declined substantially in recent years.
Examining three years of birth records and pesticide data, scientists from the Public Health Department determined that the Central Valley women lived within 500 meters, or 547 yards, of fields sprayed with organochlorine pesticides during their first trimester of pregnancy. Eight of them, or 28%, had children with autism. Their rate of autism was six times greater than for mothers who did not live near the fields, the study said.