Maternal Residence Near Agricultural Pesticide Applications and Autism Spectrum Disorders among Children in the California Central Valley

Abstract

BackgroundAmbient levels of pesticides (“pesticide drift”) are detectable at residences near agricultural field sites.ObjectiveOur goal was to evaluate the hypothesis that maternal residence near agricultural pesticide applications during key periods of gestation could be associated with the development of autism spectrum disorders (ASD) in children.MethodsWe identified 465 children with ASD born during 1996–1998 using the California Department of Developmental Services electronic files, and matched them by maternal date of last menstrual period to 6,975 live-born, normal-birth-weight, term infants as controls. We determined proximity to pesticide applications using California Department of Pesticide Regulation records refined using Department of Water Resources land use polygons. A staged analytic design applying a priori criteria to the results of conditional logistic regressions was employed to exclude associations likely due to multiple testing error.ResultsOf 249 unique hypotheses, four that described organochlorine pesticide applications—specifically those of dicofol and endosulfan—occurring during the period immediately before and concurrent with central nervous system embryogenesis (clinical weeks 1 through 8) met a priori criteria and were unlikely to be a result of multiple testing. Multivariate a posteriori models comparing children of mothers living within 500 m of field sites with the highest nonzero quartile of organochlorine poundage to those with mothers not living near field sites suggested an odds ratio for ASD of 6.1 (95% confidence interval, 2.4–15.3). ASD risk increased with the poundage of organochlorine applied and decreased with distance from field sites.ConclusionsThe association between residential proximity to organochlorine pesticide applications during gestation and ASD among children should be further studied.

Birth Prevalence of Autism Spectrum Disorders in the San Francisco Bay Area by Demographic and Ascertainment Source Characteristics

“…Birth prevalence is also not affected by in-migration, which may be important for studying environmental or other factors during the appropriate susceptibility period, e.g., in utero or very early in life. We have successfully used the cases in our database or the DDS file to study such factors (Roberts et al 2007;Windham et al 2006Windham et al , 2009). …”

The link between oral contraceptive use and prevalence in autism spectrum disorder

“…Shaw suggested that the increase in the use of acetaminophen in genetically vulnerable children, and the use of acetaminophen by pregnant women may be causal [19]. Roberts et al investigated organophosphate pesticides and suggested that women living near pesticide applications might explain the increase in ASD [20]. In 2013, Zhou et al suggested infant exposure to excess multivitamins as a potential risk factor [21].…”

Autism spectrum disorder prevalence and associations with air concentrations of lead, mercury, and arsenic

“…To date, the etiology of ASD has been poorly defined; however, some studies have suggested that ASD may be caused by interactions of susceptible genes with the environment in which environmental triggers may alter gene expression (Volk et al 2014;Blake et al 2013;LaSalle 2013;Herbert et al 2006). Therefore, several investigators have examined the relationships between ASD and exposures to pesticides (Shelton et al 2012;Roberts et al 2007), ambient particulate matter (Becerra et al 2013;Volk et al 2014;Volk et al 2011), and heavy metals (Adams et al 2013;Rahbar et al 2013;Rahbar et al 2012;Shelton et al 2012;Adams et al 2007;Roberts et al 2007;Adams et al 2006;Palmer et al 2006), but results have been conflicting.…”