Early-Life Exposure to Environmental Air Pollution and Autism Spectrum Disorder: A Review of Available Evidence

Abstract

The number of children diagnosed with Autism Spectrum Disorder (ASD) has rapidly increased globally. Genetic and environmental factors both contribute to the development of ASD. Several studies showed linkage between prenatal, early postnatal air pollution exposure and the risk of developing ASD. We reviewed the available literature concerning the relationship between early-life exposure to air pollutants and ASD onset in childhood. We searched on Medline and Scopus for cohort or case-control studies published in English from 1977 to 2020. A total of 20 articles were selected for the review. We found a strong association between maternal exposure to particulate matter (PM) during pregnancy or in the first years of the children’s life and the risk of the ASD. This association was found to be stronger with PM2.5 and less evident with the other pollutants. Current evidence suggest that pregnancy is the period in which exposure to environmental pollutants seems to be most impactful concerning the onset of ASD in children. Air pollution should be considered among the emerging risk factors for ASD. Further epidemiological and toxicological studies should address molecular pathways involved in the development of ASD and determine specific cause–effect associations.

Dynamic and Systemic Perspective in Autism Spectrum Disorders: A Change of Gaze in Research Opens to A New Landscape of Needs and Solutions

“…Figure 2 summarizes the most relevant risk factors in ASD, as well as the interventions that could reduce or prevent their effects. [14,50,60,83,[275][276][277][278][279][280][281][282][283][284]. The picture shows some of the most relevant risk factors for ASD.…”

“… Risk factors for neurodevelopment and suggestions for clinical practice [ 14 , 50 , 60 , 83 , 275 , 276 , 277 , 278 , 279 , 280 , 281 , 282 , 283 , 284 ]. The picture shows some of the most relevant risk factors for ASD.…”

“…Figure 2. Risk factors for neurodevelopment and suggestions for clinical practice[14,50,60,83,[275][276][277][278][279][280][281][282][283][284].The picture shows some of the most relevant risk factors for ASD. We mention only maternal risk factors, however also some paternal characteristic (in particular, age > 40) are a risk factor for ASD.…”

Differential Effects of Urban Particulate Matter on BV2 Microglial-Like and C17.2 Neural Stem/Precursor Cells

“…Epidemiological and systematic reviews of data suggest that there is a marked association between gestational exposure to PM and risk of ASD, and that this linkage is driven by exposure to smaller particles, e.g., <PM 2.5 [58, 59]. However, data on the risks associated with other air pollutants such as nitrogen dioxide and ozone are more variable as is the identification of a critical “exposure window” during gestation.…”

Potential of Salivary Biomarkers in Autism Research: A Systematic Review

“…The prevalence of ASD is rising considerably worldwide with a higher prevalence in male than in female patients, with an estimated ratio of 4:1 [ 2 ]. Several factors contributing to ASD development are considered relevant, and key roles are played by genetics, environmental factors, and parental health status/health status of the mother [ 3 , 4 ]. As a consequence of these factors, several candidate genes, polymorphism, and/or the related disbalance of neuropeptides and steroid hormones have been defined as related to ASD pathogenesis [ 5 , 6 ].…”