Early-Life Environmental Exposure Determinants of Child Cognition and Mental Health

Abstract

There is increase concerns over child behavioral problems due to changing environments. Children are typically exposed to a long list of industrial chemicals that are neurotoxic but also to beneficial environmental factors such as spending longer periods surrounded by green spaces. In HELIX, we systematically tested the associations of an extensive set of exposures measured during pregnancy and childhood in 1,301 mother-child pairs, including outdoor and urban factors, chemical pollutants, indoor air pollutants, lifestyle and social factors. Cognitive function, emotional and behavioral problems were assessed at 6-11 yrs through the Raven Test Score (fluid Intelligence) and the standardized parent reports of child behaviour checklist (CBCL). An agnostic exposome-wide analysis considering each exposure independently was applied to assess exposome-neurodevelopment associations.Initial analyses for behavioral problems identified one out of 92 prenatal exposures significantly associated and 4 out of 110 post-natal exposures after multiple testing correction. It included an increase in symptom incidence with maternal tobacco smoking (0.34 [0.19,0.48]), also observed with an increase in emotional problems (0.20 [0.06,0.34]). No prenatal exposures remained associated with cognition after correction. In the child’s exposome, child organic food intake (1.33 [0.64, 2.02]) was associated with Raven score and healthy diet (KIDMED index) was related with decreased symptoms in behavioral problems (-0.13[-0.19,-0.07]) but indoor air pollution was related to increased symptoms. These preliminary findings showed beneficial associations of child lifestyle factors with cognitive and behavior outcomes but also raised particular concerns for smoking and indoor air pollutants. Further analyses with other cognitive and behavior domains and population stratification will give us a major picture of the exposome effects.