Autism Spectrum Disorder and Particulate Matter Air Pollution before, during, and after Pregnancy: A Nested Case–Control Analysis within the Nurses’ Health Study II Cohort

Abstract

BackgroundAutism spectrum disorder (ASD) is a developmental disorder with increasing prevalence worldwide, yet has unclear etiology.ObjectiveWe explored the association between maternal exposure to particulate matter (PM) air pollution and odds of ASD in her child.MethodsWe conducted a nested case–control study of participants in the Nurses’ Health Study II (NHS II), a prospective cohort of 116,430 U.S. female nurses recruited in 1989, followed by biennial mailed questionnaires. Subjects were NHS II participants’ children born 1990–2002 with ASD (n = 245), and children without ASD (n = 1,522) randomly selected using frequency matching for birth years. Diagnosis of ASD was based on maternal report, which was validated against the Autism Diagnostic Interview-Revised in a subset. Monthly averages of PM with diameters ≤ 2.5 μm (PM2.5) and 2.5–10 μm (PM10–2.5) were predicted from a spatiotemporal model for the continental United States and linked to residential addresses.ResultsPM2.5 exposure during pregnancy was associated with increased odds of ASD, with an adjusted odds ratio (OR) for ASD per interquartile range (IQR) higher PM2.5 (4.42 μg/m3) of 1.57 (95% CI: 1.22, 2.03) among women with the same address before and after pregnancy (160 cases, 986 controls). Associations with PM2.5 exposure 9 months before or after the pregnancy were weaker in independent models and null when all three time periods were included, whereas the association with the 9 months of pregnancy remained (OR = 1.63; 95% CI: 1.08, 2.47). The association between ASD and PM2.5 was stronger for exposure during the third trimester (OR = 1.42 per IQR increase in PM2.5; 95% CI: 1.09, 1.86) than during the first two trimesters (ORs = 1.06 and 1.00) when mutually adjusted. There was little association between PM10–2.5 and ASD.ConclusionsHigher maternal exposure to PM2.5 during pregnancy, particularly the third trimester, was associated with greater odds of a child having ASD.CitationRaz R, Roberts AL, Lyall K, Hart JE, Just AC, Laden F, Weisskopf MG. 2015. Autism spectrum disorder and particulate matter air pollution before, during, and after pregnancy: a nested case–control analysis within the Nurses’ Health Study II cohort. Environ Health Perspect 123:264–270; http://dx.doi.org/10.1289/ehp.1408133

Fine particulate matter and the risk of autism spectrum disorder

“…Other investigations of air pollution and autism have found an increased risk for autism associated with exposure to PM 2.5 (Becerra et al, 2013;Raz et al, 2014) and PM 10 (Kalkbrenner, 2015). Becerra estimated exposures with data from air monitoring stations and a land use regression model in a California study.…”

A Systematic Review of the Interplay Between Social Determinants and Environmental Exposures for Early-Life Outcomes

“…Instead, the cognitive/ behavioral studies tended to focus on environmental contaminants with known neurotoxic effects (e.g., lead, PCBs). While focusing on traditional neurotoxic exposures is logical, the omission of air quality was surprising given the associations between air pollution and neurodevelopmental outcomes across childhood [70], including recent evidence linking prenatal exposure to air pollution with autism risk [71,72]. Moreover, it is well understood that poor air quality is socially patterned with the most vulnerable families being particularly at risk [73].…”

Air Quality, Health and Community Action

“…The associations were stronger for boys than girls [69]. The third trimester of pregnancy appears to have the strongest association with the health impact of the concentration of air pollutants on autism [66]. Living near a freeway was associated with autism [90].…”