In the year 2000, one in 150 children in the U.S. was diagnosed with autism. Today, one in 68 children is diagnosed with autism spectrum disorder. New Jersey maintains the highest rates of autism with one in 45 children being diagnosed with autism. The third study of its kind, new research published this week in Environmental Health Perspectives by UC Davis MIND Institute looked at 1,000 participants and has found that children with mothers who are exposed to agricultural pesticides while pregnant might be at an increased risk for autism. They found that women who lived less than a mile from an area treated with three kinds of pesticides were 60 percent more likely to have a child with developmental delays.
The study used the California Pesticide Use Report which shows what pesticides are applied and where. Researchers mapped where the participants inhabited during pregnancy and near the time of the birth, with about one-third of study participants living about a mile from a site where commercial pesticides were used. The risk for autism decreased the farther from the pesticides that the women lived. Experts state that the developing fetal brain may be particularly vulnerable to pesticides. A 2007 study by the California Department of Public Health had similar findings.
During developmental delay, children take more time to reach communication, social and motor skills milestones. This affects about 4 percent of the U.S. children. Epidemiologic studies have already shown that exposing pesticides to pregnancy is associated with a lower IQ. The study also noted that women who are exposed to pesticides while in their second or third trimesters were even more likely to have a baby with developmental delays, like autism. The study looked at exposure to four different pesticides including organochlorines, organophosphates, pyrtheroids and carbamates. These are used on a variety of crops including oranges, cantaloupe, cotton and alfalfa. Around 1.7 million pounds of pesticides were applied in various counties in California in 2012.
Dr. Philip J. Landrigan, who directs the Children’s Environmental Health Center at the Icahn School of Medicine at Mount Sinai in New York stated that the pesticides most likely drifted from nearby crops through the air, and that is how the pregnant women became exposed. However, the new study failed to measure pesticide levels in the air. Dr. Landrigan was not involved in the study. It must still be determined whether exposure to household pesticides pose a similar threat to pregnant women. Further research is also needed to determine the role a woman’s genes play in having a child with autism.
A separate study published this week in Pediatrics has linked race and autism spectrum disorders. Over 7,500 people were studied and the results found that Central and South American, Vietnamese, Filipino and foreign-born black mothers were all at an increased risk for developing autism when compared with the children of white mothers. This association does not necessarily imply cause however. Several other risk factors are at work that may be increasing the risk for autism, for example, maternal stress or nutritional deficiencies. Both studies show the need for enhancing out understanding the link between exposure to pesticides and autism, especially when it comes to pregnant women.
By Samantha Levy