Single and combined effects of prenatal exposure to air pollutants on children's cognitive performance.

BACKGROUND

Prenatal air pollution exposure has been increasingly recognised for its impact on children's cognitive development and overall health. This study explored the association between prenatal exposure to air pollutants and cognitive performance in two age groups of children, also assessing combined pollutants and identifying sensitive prenatal exposure windows.

METHODS

A total of 781 children were included: 295 preschool-aged (4-5 years) and 486 school-aged (10-11 years), recruited from the EPINED epidemiological project in Tarragona, Spain. Cognitive performance was assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV) and Wechsler Intelligence Scale for Children (WISC-IV). Associations were examined using linear distributed lag models, and combined effects of pollutants were evaluated using weighted quantile sum regression, adjusting for socio-familial, individual, and environmental factors.

RESULTS

In preschool-aged children, PM2.5, PM2.5abs, PMcoarse, PM10, NOx, and NO2 were associated with lower fluid reasoning [β = -0.97-(-2.29)], working memory [β = -0.82-(-3.79)] and full-scale IQ [β = -0.63-(-2.08)]. In school-aged children, most pollutants were associated with reduced verbal comprehension [β = -0.87-(-3.84)] and full-scale IQ [β = -0.85-(-1.99)] and subtle effects were observed for perceptual reasoning and working memory. Across both age groups, these associations were greater during the third trimester. Whereas the combined pollutant effects indicated the second trimester as a critical window for verbal comprehension in school-aged children, suggesting pollutant contribution varies across gestation.

CONCLUSIONS

Prenatal exposure to air pollutants, particularly in late pregnancy, is associated with lower full-scale IQ and other aspects of cognitive performance, highlighting critical windows of vulnerability for foetal brain development.