Association of early life exposure to PM2.5 and its components with offspring neurodevelopment: A prospective birth cohort study.

Abstract

Emerging data have explored early life fine particulate (PM_2.5) exposure and its relationship with offspring neurodevelopment. However, the findings remain inconsistent, and the roles of specific PM_2.5 components are unclear. We investigated these associations and explored the potential interactive role of children's physical activity (PA). A total of 1547 mother-child pairs from the Shenzhen Birth Cohort were included. Neurodevelopment was assessed at seven time points (1, 3, 6, 8, 12, 18, and 24 months) using the Ages and Stages Questionnaire. An established spatiotemporal model was used to estimate early life exposure to PM_2.5 and five components [sulfate (SO₄²), nitrate (NO₃^-), ammonium (NH₄⁺), organic matter (OM), and black carbon (BC)]. Associations of individual and joint exposure to components with neurodevelopment were analyzed using generalized estimating equation and quantile-based g-computation models with a binomial distribution. Most mothers (79.1%) were under 35 at delivery, and 43.6% of the children were boys. During the early postnatal period, a 5 μg/m³ increase in PM_2.5 was associated with higher adjusted odds ratios (aORs) for developmental delays in gross motor (1.24, 95%CI:1.12, 1.37), fine motor (1.11, 95%CI:1.04, 1.20), and problem-solving (1.12, 95%CI:1.03, 1.22) domains. Similar associations were observed for individual PM_2.5 components. Each quintile increase in early postnatal exposure to PM_2.5 mixtures was correlated with higher aORs for these domains, with NO₃^- constituting the largest weight. No significant associations were found for the prenatal period. The children's PA showed no interaction. These findings underscore the need to reduce PM_2.5 exposure, particularly its toxic components, to minimize developmental risks.