AMBIENT AIR POLLUTION AND COGNITIVE FUNCTIONS IN SCHOOL-AGED CHILDREN IN ACCRA, GHANA

Emerging evidence has linked ambient air pollution to cognitive function in children, but evidence is lacking for Sub-Saharan Africa (SSA) where air pollution levels are rising in fast-growing cities. We examined the associations between ambient air pollution exposure and cognitive function in schoolchildren in Accra, Ghana, one of the fastest growing metropolises in SSA. Our analysis involved 862 children (ages 8–12) from 90 elementary schools (75% public) recruited within the Accra School Health and Environment Study (ASHES). Cognitive functions including executive function, attention, processing speed, working memory, and episodic memory were assessed using the NIH Toolbox cognition battery. Ambient PM2.5, BC, and NO2 exposures were estimated using land-use regression models linked with the children’s home and school locations. We estimated covariate-adjusted associations of the individual exposures with the outcomes using linear mixed-effects models, Generalized Additive Models (GAM), and of mixtures using quantile G-computation. The mean scores of the different cognitive function measures were: Flanker (6.40, range: 0–9.50), Card Sort (5.94, range: 0–9.60), List Sort (13.00, range: 0–26.00), Pattern Comparison (33.75, range: 11.00–56.00), Picture Sequence (-1.13, range: -2.19–1.55), and Composite (78.2, range: 44-112). The annual exposures of PM2.5, BC, and NO2, ranged 28.6–39.5, 3.51–10.3, and 21.8–103.6, respectively. We observed small inverse but nonsignificant associations between each pollutant and cognitive measures in all models. The effect of NO2 on Flanker was significant in males (p-interaction < 001), while PM2.5 was significant in private schoolchildren (-0.085, 95% CI: -0.175, -0.001). We found no evidence of associations between ambient air pollution and cognitive function in Ghanaian schoolchildren. Additional studies, particularly, prospective studies investigating specific windows of susceptibility are needed to understand its broader implications for public health Keywords: cognitive function, air pollution, children, Africa, NIH Toolbox