Reduced gray matter volume and cortical thickness associated with traffic-related air pollution in a longitudinally studied pediatric cohort

Abstract

Early life exposure to air pollution poses a significant risk to brain development from direct exposure to toxicants or via indirect mechanisms involving the circulatory, pulmonary or gastrointestinal systems. In children, exposure to traffic related air pollution has been associated with adverse effects on cognitive, behavioral and psychomotor development. We aimed to determine whether childhood exposure to traffic related air pollution is associated with regional differences in brain volume and cortical thickness among children enrolled in a longitudinal cohort study of traffic related air pollution and child health. We used magnetic resonance imaging to obtain anatomical brain images from a nested subset of 12 year old participants characterized with either high or low levels of traffic related air pollution exposure during their first year of life. We employed voxel-based morphometry to examine group differences in regional brain volume, and with separate analyses, changes in cortical thickness. Smaller regional gray matter volumes were determined in the left pre-and post-central gyri, the cerebellum, and inferior parietal lobe of participants in the high traffic related air pollution exposure group relative to participants with low exposure. Reduced cortical thickness was observed in participants with high exposure relative to those with low exposure, primarily in sensorimotor regions of the brain including the pre-and post-central gyri and the paracentral lobule, but also within the frontal and limbic regions. These results suggest that significant childhood exposure to traffic related air pollution is associated with structural alterations in brain.

Air pollution and neurological development in children

“…Neuroimaging studies show that childhood exposures to traffic-related air pollutants such as PM 2.5 can induce changes in the brain's cerebral white matter, cortical gray matter, and the basal ganglia, all of which may have implications for cognition. 29,44,45 A literature review of 31 studies on the effects of air pollution and developmental health across the lifespan suggest that higher pollution exposure in childhood is inversely associated with academic achievement and cognitive performance in children. 46 Early-life exposure is also associated with a reduction in fundamental cognitive abilities, including working memory, conflict attentional network, and, more recently, atypical excitatory neurotransmission and glial inflammatory responses that may have important implications on anxiety disorders.…”

“…These complications range from alteration in the subclinical brain structure to overt signs and symptoms or diagnosis of neuropsychological disorders such as ADHD and ASD. Neuroimaging studies show that childhood exposures to traffic‐related air pollutants such as PM 2.5 can induce changes in the brain’s cerebral white matter, cortical gray matter, and the basal ganglia, all of which may have implications for cognition 29,44,45 . A literature review of 31 studies on the effects of air pollution and developmental health across the lifespan suggest that higher pollution exposure in childhood is inversely associated with academic achievement and cognitive performance in children 46 .…”

Solid cooking fuel use and cognitive decline among older Mexican adults

“…Outdoor air pollution is associated with expression of inflammatory mediators in the frontal cortex and hippocampus 54 and pro‐inflammatory cytokines in the hippocampus 55 as well as neuroinflammation in the olfactory bulb and the hippocampus 56 . Individuals with higher exposure to outdoor air pollution also have been reported to have smaller white matter volumes, 57 total cerebral volume, 58 and decreased cortical thickness and gray matter volume 59 …”

Impact of Environmental Injustice on Children’s Health—Interaction between Air Pollution and Socioeconomic Status

“…Outdoor air pollution has been associated with a child’s academic performance [ 33 ], which can further continue the cycle of income inequality, as higher education allows for people to get jobs with higher salary. Furthermore, traffic-related air pollution is associated with structural alterations in the brain, such as reduced regional grey matter and cortical thickness [ 34 ]. Children from schools in highly polluted environments had a smaller growth in cognitive development than children from the schools in lowly polluted areas.…”