Maternal exposure to aircraft emitted ultrafine particles during pregnancy and likelihood of ASD in children

Abstract

Background: There is increasing evidence for adverse health effects associated with aircraft-emitted particulate matter (PM) exposures, which are largely in the ultrafine (PM_0.1) size fraction, but no previous study has examined neurodevelopmental outcomes.

Objective: To assess associations between maternal exposure to aircraft ultrafine particles (UFP) during pregnancy and offspring autism spectrum disorder (ASD) diagnosis.

Methods: This large, representative cohort study included 370,723 singletons born in a single healthcare system. Demographic data, maternal health information, and child's ASD diagnosis by age 5 were extracted from electronic medical records. Aircraft exposure estimates for PM_0.1 were generated by the University of California Davis/California Institute of Technology Source Oriented Chemical Transport model. Cox proportional hazard models were used to assess associations between maternal exposure to aircraft PM_0·1 in pregnancy and ASD diagnosis, controlling for covariates.

Results: Over the course of follow-up, 4,554 children (1.4 %) were diagnosed with ASD. Increased risk of ASD was associated with maternal exposure to aircraft PM_0.1 [hazard ratio, HR: 1.02, (95 % confidence interval (CI): 1.01-1.03) per IQR = 0.02 µg/m³ increase during pregnancy. Associations were robust to adjustment for total PM_0.1 and fine particulate matter (PM_2.5), near-roadway air pollution, and other covariates. Noise adjustment modestly attenuated estimates of UFP effects, which remained statistically significant.

Discussion: The results strengthen the emerging evidence that maternal particulate matter exposure during pregnancy is associated with offspring ASD diagnosis and identify aircraft-derived PM_0.1 as novel targets for further study and potential regulation.

Keywords: Air pollution; Aircraft emissions; Autism spectrum disorders; Childhood neurodevelopment.