Outdoor residential air pollution exposure and the development of brain morphology across childhood: a longitudinal study

Abstract

Background and aim: Emerging evidence suggests a relationship between exposure to air pollution and brain morphology in children, but little is known about how air pollution exposure influences the development of brain structures throughout childhood. We aim to study the association of air pollution exposure during pregnancy and childhood with the development of brain morphology from age 6-16 years. Methods: We used data from 4,243 children of the Generation R study, a birth cohort in Rotterdam, the Netherlands. We estimated the concentrations of fourteen air pollutants at participant´s home addresses during pregnancy and childhood, using land use regression models. We included structural brain images at three time points, namely at age 6-10 years, 9-12 years, and 13-16 years. We assessed the association between the air pollutants and brain volumes with linear mixed models, fitting an interaction term for age and each pollutant. Models were adjusted for socioeconomic status and lifestyle characteristics. Results: Higher air pollution exposure during pregnancy was associated with a slower decrease of cortical grey matter volume starting at around age 10 and a slower increase of corpus callosum volume (e.g. -12.7 mm3 increase in corpus callosum volume [95%CI -22.0; -3.3] with each year of age per 10 μg/m3 increase in nitrogen dioxide exposure). Childhood exposure was associated with a faster decrease of putamen and caudate nucleus volume, and a slower increase of hippocampus volume. Higher exposure to air pollution during pregnancy and childhood was associated with a slower increase of thalamus volume. Air pollution exposure was not associated with cerebellum, amygdala, nucleus accumbens or globus pallidus volume. Conclusions: Air pollution exposure was associated with region-specific differences in age-related growth trajectories. Air pollution exposure during childhood might affect different brain regions than exposure during pregnancy. Keywords: air pollution, neurodevelopment, children, traffic