Early life exposure to fine particulate matter and fine motor function, attentional function, and working memory...

Evidence of the association between fine particulate matter (PM_2.5) exposure and child neuropsychological function is equivocal. We examined early life PM_2.5 exposure in relation to fine motor function, attention, and working memory in early childhood.

We used data from the Spanish INfancia y Medio Ambiente Project, 2003-2008. Exposure to PM_2.5 (μg/m³) was assessed using spatiotemporal land-use random forest models and assigned based on residential address histories. Around age six, children completed the finger tapping test, attentional network test (ANT), and n-back task to evaluate fine motor speed, attention, and working memory, respectively. A total of 1,310 children had data from at least one neuropsychological assessment. General linear models were applied to assess associations between average prenatal and postnatal PM_2.5 with each outcome. Distributed lag nonlinear models were used to explore refined periods of susceptibility to PM_2.5. We reported β estimates and 99% credible intervals (CrI) representing the change in each outcome per 5-μg/m³ increase in PM_2.5.

Prenatal PM_2.5 exposure was associated with decreased mean hit reaction time (HRT) (β = -21.82; 99% CrI = -64.1, 20.4) and HRT-standard error (β = -9.7; 99% CrI = -30.3, 10.9) on the ANT but estimates were imprecise. Postnatal PM_2.5 was associated with reduced mean HRT on the n-back task (β = -39.4; 99% CrI = -115.1, 26.3). We observed sensitive periods of exposure in the postnatal period associated with both better and worse performance on the finger-tapping test and ANT.

We found limited evidence to support an association between PM_2.5 exposure and fine motor function, attentional function, or working memory in school-aged children.