Prenatal exposure to environmental pollutants and child development trajectories through 7 years

Background: Prenatal exposure to environmental pollutants such as mold, lead, pesticides, tobacco, and air pollutants has been suggested to impair cognitive development. Evidence is needed from longitudinal studies to understand their joint impact on child development across time. Objective: To study associations between exposure to indoor environmental pollutants or outdoor air pollution during pregnancy and offspring cognitive development trajectories through 7 years. Methods: We included 718 Mexican mother-child pairs. Prenatal exposure to indoor environmental pollutants (mold, ventilation, pesticides, tobacco smoke, and use of vidiartred clay pots) was self-reported by the mothers and integrated into an index, or objectively measured in the case of outdoor air pollutants (nitrogen oxides, benzene, toluene, and xylene). Child global cognitive development was measured at 12, 18, 60, or 84 months. Using Latent Class Growth Analysis, we identified three developmental trajectories (positive = 108, average = 362, low = 248). We used multinomial logistic models to test associations between environmental pollutant score (EPS) or outdoor air pollutants, and cognitive development trajectories. Results: After adjustment for sociodemographic covariates, EPS was associated with the average (OR = 1.26 95%CI = 1.01, 1.55) and low (OR = 1.41 95%CI = 1.11, 1.79) trajectories compared to positive; where a unit increase in EPS means an additional prenatal exposure to a pollutant. There was no association between outdoor air pollutants and cognitive development trajectories. Conclusion: Children of women who reported higher exposure to indoor environmental pollutants during pregnancy were more likely to follow worse developmental trajectories through 7 years. These results support the development and testing of interventions to reduce exposure to environmental pollutants during pregnancy and early childhood as a potential strategy to improve long-term cognitive development.