Prenatal and preschool age lead exposure: Relationship with size

Abstract

This report examines possible adverse effects on size and growth associated with subclinical prenatal and preschool age lead exposure in an urban cohort followed prospectively from birth through early childhood. Measurements of weight, stature (length), and head circumference were obtained at birth and during five subsequent in-home assessments. Prenatal lead exposure was assessed by cord (n = 185) and maternal (n = 162) blood lead levels at delivery. Preschool blood lead samples were obtained at ages six months (n = 151), two years (n = 165), three years (n = 165), and four years, ten months (n = 164). Multivariate longitudinal analyses incorporating adjustment for covariates revealed no statistically significant adverse effects of prenatal lead exposure on either neonatal size or on subsequent growth through age four years, ten months. Similarly, no statistically significant adverse effects were found between the preschool lead indices derived from blood collected at or after age two years and ensuing size measurements. We also found no evidence for an interaction between pre- and postnatal lead exposure. A marginal inverse association was exhibited between blood lead at six months and subsequent measures of head circumference. Limitations in the implications of this result in the context of many nonsignificant tests were discussed.