Prenatal Lead Exposure and Child Development

We use data from an ELEMENT (Early Life Exposures in Mexico to Environmental Toxicants) study cohort of mother–child pairs recruited during pregnancy or before conception (Téllez-Rojo et al. 2004 (link)). We use maternal blood lead concentrations ascertained during study visits scheduled within each trimester. Low birth weight (< 2,500 g) and preterm (< 37 weeks) children were excluded. Children’s mental development was measured at 24 months using Bayley’s Mental Development Index (MDI24) (Bayley 1993 ). We also collected other participant characteristics (Table 1); data collection procedures are reported elsewhere (Hu et al. 2006 (link); Téllez-Rojo et al. 2004 (link)). This analysis was restricted to n = 169 participants with complete covariates (mother’s age and IQ, breast-feeding duration, and child’s sex, height, weight, and blood lead level at 24 months) and at least one measure of prenatal lead exposure.
Participants gave written informed consent before data collection. The study was approved by the institutional review boards of the hospitals where participants were recruited, the National Institute of Public Health of Mexico, Brigham and Women’s Hospital, Harvard School of Public Health, and the University of Michigan.