Exposure to ambient air pollution & executive function among Chinese primary schoolchildren

Abstract

Background: Evidence on the association between particulate matter (PM) and nitrogen dioxide (NO2) exposure with executive function in children is scarce in developing countries. Moreover, few studies investigated ozone (O3) and sulfur dioxide (SO2). This study was aimed to investigate the associations between long-term exposure to air pollution and executive function in Chinese children. Methods: In 2017, we randomly recruited 5,028 children aged 6-12 years from 5 schools in Guangzhou city, southern China. Each of 5,028 children’s executive function were assessed using parent filled questionnaire. We further randomly selected 522 children to take computerized tests to assess working memory, inhibitory control, and cognitive flexibility. Residential PM with diameters ≤2.5 (PM2.5) or 10 μm (PM10), NO2, O3, and SO2 exposures were estimated by using an inverse-distance weighting approach. Associations were evaluated by mixed linear regression models. Results: Each interquartile range increment in PM2.5 was associated with 54.02 milliseconds [95% confidence interval (CI): 5.52 to 102.52] increase in inhibitory control and 0.72 (95% CI: -1.17 to -0.27) points decrease in forward recall. PM10 exposure was associated with 0.58 (95% CI: -1.09 to -0.77) and 0.62 points (95% CI: -1.00 to -0.23) reduction in forward and backward recall, respectively. SO2 exposure was associated with 0.49 (95%CI: 0.18 to 0.80) and 0.73 (95%CI: 0.41 to 1.05) high scores of behavioral regulation index and metacognition index, respectively. Significant association was found between O3 exposure and metacognition index (estimate, 95%CI: 0.88, 0.47 to 1.30). Conclusions: Long-term exposures to PM2.5, PM10, SO2, and O3 were associated with poorer performance in working memory, inhibitory control, behavioral regulation, and metacognition in children.Key words: Air pollution; Executive Function; Child; Cognitive Neuroscience; Cross-sectional study