Duke links pesticides to 60% higher autism risk

Duke University said in a June 30, 2014 post that prenatal exposure to organophosphate pesticides was linked to a higher risk of autism in children living near treated agricultural fields. The Duke write-up summarized a National Institute of Environmental Health Sciences report published that week and said children whose mothers lived within a mile of fields treated with an organophosphate pesticide during pregnancy were 60% more likely to develop autism spectrum disorders than those who did not live near treated fields. Duke also said the study found a stronger association for chlorpyrifos exposure during the second trimester. ### Where does the “60% higher risk” figure come from? The 60% figure comes from Duke’s summary of a 2014 study in *Environmental Health Perspectives* known as the CHARGE study. The Duke post said the estimate applied to children whose mothers lived within a mile of fields treated with an organophosphate pesticide during pregnancy. (sites.nicholas.duke.edu) The underlying paper was authored by researchers including Janie F. Shelton, Rebecca J. Schmidt, Beate Ritz and Irva Hertz-Picciotto, and was published in *Environmental Health Perspectives* on June 23, 2014. The paper examined prenatal residential proximity to agricultural pesticides and neurodevelopmental disorders. ### Was this a new Duke study? The Duke page does not describe the work as a Duke-led original study. (sites.nicholas.duke.edu) The post says the National Institute of Environmental Health Sciences published a report that week linking prenatal exposure to organophosphate pesticides with higher autism risk. The named authors listed on the paper are affiliated with the University of California, Davis, UCLA and related institutes, according to the PubMed Central record. (pmc.ncbi.nlm.nih.gov) That means the claim circulating now points back to older published research that Duke summarized, rather than to a newly released Duke-authored paper. ### What exactly did the researchers measure? (sites.nicholas.duke.edu) The CHARGE study looked at residential proximity to agricultural pesticide applications during pregnancy, not direct proof that each mother or child absorbed a measured dose. Duke said the comparison was based on whether mothers lived within a mile of treated fields during pregnancy. (pmc.ncbi.nlm.nih.gov) That distinction matters because the study design identifies an association between living near applications and autism risk. Duke’s summary also said women living near agricultural fields were likely exposed to numerous pesticides during pregnancy, making it difficult to isolate the effects of a single chemical. ### Why is chlorpyrifos mentioned separately? (sites.nicholas.duke.edu) Duke said chlorpyrifos was the most commonly used organophosphate pesticide in the study context and reported that children whose mothers lived near fields treated with chlorpyrifos during the second trimester were 3.3 times more likely to develop autism. The same Duke post said organophosphates were the most commonly used pesticide class in the United States at the time and that household uses of most organophosphates had been banned by the Environmental Protection Agency in 2001, while agricultural and commercial uses continued. (sites.nicholas.duke.edu) ### How should readers frame this finding? (sites.nicholas.duke.edu) The Duke summary presents the result as an epidemiological link, not proof that pesticides alone cause autism. Duke said environmental health studies are difficult because people are exposed to many chemicals at once, and it noted that changes in diagnosis did not fully explain rising autism rates. A separate 2026 *JAMA Pediatrics* paper indexed by PubMed reported that, in a large prospective ECHO cohort study, prenatal organophosphate exposure was not associated with autism-related traits in childhood. That newer paper suggests the evidence base is still evolving and that different study designs can produce different findings. ### What should people watch next? (sites.nicholas.duke.edu) The key next step is not a new Duke release but the underlying scientific literature. Readers tracing this claim should look to the 2014 *Environmental Health Perspectives* CHARGE study and newer peer-reviewed work, including the 2026 *JAMA Pediatrics* paper, to see how evidence on prenatal organophosphate exposure and autism-related outcomes is developing. (pmc.ncbi.nlm.nih.gov) (pubmed.ncbi.nlm.nih.gov)