Prenatal Exposure to Ambient Particulate Matter and Autism Spectrum Disorder in Children, a Case Control Study in France

A series of epidemiological studies conducted in the United States have consistently shown an increased risk of autism spectrum disorder (ASD) in children associated with pre- and postnatal exposure to ambient particulate matter (PM). In Europe, studies are scarce and results are inconsistent. We aimed to investigate the association between prenatal exposure to PM and the risk of ASD in France. ASD cases were participants from the ELENA cohort. Controls children from the ELFE cohort were matched by sex, year (± 2) and region of birth. Prenatal exposures to PM10 and to PM2.5 were estimated between 2008 and 2013 using innovative hybrid spatio-temporal models developed for France. Conditional logistic regression models adjusted for birth season, parent’s age at the child birth and parental education level were run. We included 125 ASD cases and 500 controls. Prenatal PM2.5 and PM10 median (IQR) concentration estimates were respectively 16.3 (3.9) µg/m³ and 22.9 (6.6) µg/m³ in the whole sample. The conditional logistic regression models showed Odds Ratios (ORs) (Confidence Interval 95%) for ASD risk of 0.72 (0.52–1.01) and 0.84 (0.58–1.22) for an IQR increase in PM2.5 and PM10 prenatal levels, respectively. When restricting population of ASD cases to children born the same year of controls, ORs were 1.79 (0.80–4.01) and 2.23 (0.71–9.04), respectively. Our results did not show that prenatal exposures to PM2.5 and PM10 were associated with the risk of ASD in children in France.