Air pollution exposure during pregnancy and childhood autistic traits in four European population-based cohort studies: the ESCAPE project

BACKGROUND: Prenatal exposure to air pollutants has been suggested as a possible etiologic factor for the occurrence of autism spectrum disorder. OBJECTIVES: We aimed to assess whether prenatal air pollution exposure is associated with childhood autistic traits in the general population. METHODS: Ours was a collaborative study of four European population-based birth/child cohorts--CATSS (Sweden), Generation R (the Netherlands), GASPII (Italy), and INMA (Spain). Nitrogen oxides ([NO.sub.2], [NO.sub.x]) and particulate matter (PM) with diameters of < 2.5 [micro]m ([PM.sub.2.5]), [less than or equal to] 10 [micro]m ([PM.sub.10]), and between 2.5 and 10 [micro]m (PMcoarse), and [PM.sub.2.5] absorbance were estimated for birth addresses by land-use regression models based on monitoring campaigns performed between 2008 and 2011. Levels were extrapolated back in time to exact pregnancy periods. We quantitatively assessed autistic traits when the child was between 4 and 10 years of age. Children were classified with autistic traits within the borderline/clinical range and within the clinical range using validated cut-offs. Adjusted cohort-specific effect estimates were combined using random-effects meta-analysis. RESULTS: A total of 8,079 children were included. Prenatal air pollution exposure was not associated with autistic traits within the borderline/clinical range (odds ratio = 0.94; 95% CI: 0.81, 1.10 per each 10-[micro]g/[m.sup.3] increase in [NO.sub.2] pregnancy levels). Similar results were observed in the different cohorts, for the other pollutants, and in assessments of children with autistic traits within the clinical range or children with autistic traits as a quantitative score. CONCLUSIONS: Prenatal exposure to [NO.sub.2] and PM was not associated with autistic traits in children from 4 to 10 years of age in four European population-based birth/child cohort studies. http://dx.doi.org/10.1289/ehp.1408483
Introduction Autism spectrum disorders (ASD) are lifelong developmental disabilities characterized by social interaction impairment, communication deficits, and repetitive behaviors (van Engeland and Buitelaar 2008). The prevalence of ASD has increased [...]