Impact of exposure to PM2.5 in household air pollution on child neurocognitive development at seven years of age

Abstract

BACKGROUND AND AIM: 93% of the world’s children under age 15 breathe polluted air that harms their health and development. Fine-grained particulate matter (PM2.5) in household air pollution is a particular threat. A significant source of PM2.5 is use of polluting cookstoves in the home. Mothers and children suffer the highest exposures, with risks to children beginning in-utero, potentially impairing their later neurocognitive development. We examine the association between PM2.5 exposures and neurocognitive development in children at age seven. METHOD: This study follows up on a randomized controlled trial that compared effects, on Nigerian pregnant women, of cooking with polluting fuels versus ethanol. We have followed the children born to these women and measured their personal and indoor PM2.5 exposures at age seven. We assessed their neurocognitive development using the Kaufman Assessment Battery for Children, 2nd Edition (KABC-II) and the Vineland Adaptive Behavior Scales (VABS). Multiple linear regression was used to examine the association between PM2.5 exposures and neurocognitive ability, adjusting for child’s age, family assets, and mother’s education. RESULTS: Our sample of 198 children (mean age 7.2 years, SD 0.2) included 132 children from households using clean cookstoves (liquefied petroleum gas, ethanol) and 66 children from households using polluting cookstoves (firewood, charcoal). Indoor peak PM2.5 levels were higher in households with polluting stoves (geometric mean, 276 μg/m3) than those with clean stoves (192 μg/m3). Children’s PM2.5 exposure levels were inversely associated with their KABC-II and VABS scores. A 2-fold increase in child’s peak personal PM2.5 exposure was associated with a 3.9-unit reduction in KABC-II score (p0.001); a 2-fold increase in peak indoor PM2.5 exposure with a 2.0-unit reduction in VABS score (p=0.03). Clean stove use was associated with higher KABC-II scores (coef. 4.1, p=0.04). CONCLUSIONS: Household use of polluting cookstoves contributes to children’s PM2.5 exposure levels, potentially impairing their neurocognitive development.