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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT00646360.

Keywords: Air pollution; Household pollutants; Long-Term cognitive development; Mold; Pesticides; Prenatal exposure.

Conflict of interest statement

Financial Disclosure: The authors have no financial relationships relevant to this article to disclose

Potential Conflicts of Interest: The authors have no conflicts of interest relevant to this article to disclose.

Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

Figures

Figure 1

Developmental trajectoriesa from 1 to 7 years in a sample of 718 Mexican childrenb aThe figure shows average cognitive z-scores at 12, 18, 60, and 84 months of children who were classified into 3 latent classes using Latent Class Growth Analysis Models. b The first trajectory labeled ‘low’ and included 248 children (34.7%), the second trajectory, labeled “average” and included 362 children (50.4%), and the third trajectory, labeled “positive” included 108 children (14.8%)

Figure 2

Sample selection for the analysis of prenatal exposure to environmental pollutants and cognitive development trajectories through 7 years