Early exposure to agricultural pesticides and the occurrence of autism spectrum disorder: a systematic review.

Researchers looked at six studies to see if exposure to farm chemicals during pregnancy or early life might be linked to autism. They found that children exposed to these chemicals had higher rates of autism. The studies measured exposure either through chemicals found in mothers' blood or by looking at how close families lived to farms. While this suggests farm chemicals might increase autism risk, more research is needed to be sure.

This systematic review examined six case-control studies investigating the relationship between early agricultural pesticide exposure and autism spectrum disorder. Studies measured exposure through maternal biomarkers or residential proximity to agricultural areas. All included studies demonstrated moderate to high quality ratings. The review found consistently high rates of association between early agricultural pesticide exposure and autism development.

Specific chemical compounds including polychlorinated biphenyls, hexachlorobenzene, and dichlorodiphenyldichloroethylene were detected above quantification limits in exposed samples. While the evidence suggests a concerning link between early-life agricultural pesticide exposure and autism spectrum disorder development, the authors emphasize that additional research is needed to better establish and understand this potential association.

These findings suggest early agricultural pesticide exposure may be an environmental risk factor for autism spectrum disorder. However, causation cannot be established from this evidence. Families living near agricultural areas may benefit from discussing exposure risks with healthcare providers during pregnancy planning and early childhood.

Only six case-control studies were included in the review. The authors explicitly state that more studies are required to better understand the possible association between agricultural pesticide exposure and autism spectrum disorder.

The aim of this study was to evaluate the influence of early exposure to agricultural pesticides and their relationship with autism spectrum disorder. This systematic review was registered at PROSPERO as CRD42020204842. The subject was systematically analyzed on PubMed, Scopus, and Web of Science databases until April 2021. Only studies with humans with early exposure to agricultural pesticides and diagnosis of autism were included.

Exclusion criteria were studies on pesticides for domestic or veterinary use and late exposure. There were no language and time restriction. The quality analysis of the studies used the Newcastle-Ottawa Scale. Six case-control studies were included; three of them measured the route of exposure by maternal biomarkers and the others by the residence address.

The studies had scores between moderate and high in the quality assessment tool. It was found high rates of association between early exposure to agricultural pesticides and autism and detection limit above the quantification for a sample of polychlorinated biphenyls, hexachlorobenzene, and dichlorodiphenyldichloroethylene. There is evidence concerning the exposure to agricultural pesticides in early life and the development of the autism spectrum disorder; however, more studies are required to better understand their possible association.