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.
For The Record
Los Angeles Times Tuesday July 31, 2007 Home Edition Main News Part A Page 2 National Desk 1 inches; 65 words Type of Material: Correction
Autism link: An article in Monday's California section about a new state study that found that exposure to two pesticides may make women more likely to give birth to children with autism said it was the first study to find a link between pesticides and autism. Italian scientists reported in 2005, however, that pesticides known as organophosphates could cause neurological changes that lead to autism.
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.
Susan Kegley, senior scientist of Pesticide Action Network North America, a San Francisco-based advocacy group, said the report adds to an existing body of evidence that endosulfan and dicofol, already banned in some countries, are harmful.
"This is one of the first papers that links use of pesticide to incidence of a disease, and autism in particular," she said. "The findings are very strong. This is a sixfold risk factor in comparison to someone who is not exposed. There aren't too many studies that come out like that."
Even though small numbers of children were involved, "it is still one of those things that make you sit up and pay attention," she said.
