Background: Air pollution from traffic has been associated with cardiorespiratory diseases in children and adults, but there is little information on its potential neurotoxic effects. This study aimed to investigate the association between exposure to NO2, as a marker of traffic-related air pollution, and cognitive development in children.
Methods: A population-based birth cohort from Southern Spain was followed up from the age of 4 yrs for one year. Complete data for analyses were gathered on 210 children living in urban and rural areas. NO2 exposure was predicted by means of land use regression models. A standardized version of the McCarthy Scales of Children's Abilities (MSCA) was used to assess children's motor and cognitive abilities. Multivariate analyses were performed to evaluate the relation between exposure to NO2 and MSCA outcomes, adjusting for potential confounders.
Results: A negative effect of NO2 was found across all MSCA sub-scales, despite low predicted NO2 exposure levels (5-36 μg/m3). Children exposed to higher NO2 (>24.75 μg/m3) showed a decrease of 4.19 points in general index score and decreases of 6.71, 7.37, and 8.61 points in quantitative, working memory, and gross motor areas, respectively. However, except for gross motor function, associations were not statistically significant.
Conclusion: Although results were not statistically significant, the associations found between exposure to NO2 and cognitive functions suggest that traffic-related air pollution may have an adverse effect on neurodevelopmentween, especially early in life, even at low exposure levels.