Perinatal & Pediatric
Lead Exposure During Key Neurodevelopmental Stages: A Target Trial Using Multimedia Biomarkers to Assess Children’s Cognitive Function in Mexico City Victor Florez-Garcia* Victor Florez-Garcia Alexander Keil Amy Kalkbrenner
Background: Lead exposure is particularly harmful to neurodevelopment when it occurs during pregnancy and early childhood. Quantifying the impact of exposure reduction can help policymakers establish evidence-based thresholds from a public health perspective. Objective: This study aimed to evaluate the causal effect of hypothetical interventions restricting the use of lead-glazed pottery in Mexico City during pregnancy and early childhood on children’s cognitive performance. Methods: We used data from the Programming Research in Obesity, Growth, Environment, and Social Stressors (PROGRESS) longitudinal birth cohort in Mexico City. Lead exposure levels were assessed in blood, urine, and hair during both pre- and postnatal periods. Children’s intellectual functioning was measured using the McCarthy Scales of Children’s Abilities, focusing on verbal, perceptual, and quantitative domains, as well as the composite General Cognitive Index (GCI). Multi-media biomarker (MMB) indexes were developed using Weighted Quantile Sum Regression (WQS) and Principal Component Analysis (PCA). G-computation was applied to estimate adjusted observed and predicted effect sizes (β) along with 95% confidence intervals (95%CIs). Results: We observed an increase in the General Cognitive Index score, with a maximum gain of 0.60 points [95%CI: -0.25, 1.46]. The MMB-WQS method demonstrated a greater effect than MMB-PCA for perceptual and quantitative scales. The highest cognitive gains occurred with a 40% reduction in lead exposure, yielding improvements in perceptual [Δβ:0.77; 95%CI:0.24, 1.30] and quantitative abilities [Δβ:0.51; 95%CI: -0.05, 1.08]. Conclusion: Our findings suggest that reducing lead exposure during pregnancy and early childhood—particularly by limiting or banning lead-glazed pottery—could enhance children’s cognitive development by 48 months of age in Mexico City.