EARLY LEAD-EXPOSURE AND NEONATAL JAUNDICE - RELATION TO NEUROBEHAVIORAL PERFORMANCE AT 15 YEARS OF AGE

A cohort of children who attended first grade in 1983 was identified in a Danish community with low-level lead pollution. Two groups with high and low postnatal lead exposure were generated on the basis of the dentin-lead concentration in shed deciduous incisors. At age 8 years, examination of 162 children matched according to gender and socioeconomic status had shown lead-related deficits in verbal intelligence and visuomotor coordination. Re-examination was now carried out in 141 children at age 15 years using the Wechsler Intelligence Scale for Children (WISC), Bender Visual Motor Gestalt, Trail Making, and Visual Gestalts. In general, no lead-related effects could be detected in the group. However, in children with a history of neonatal jaundice, increased lead exposure was associated with mild neurobehavioral deficits, as indicated by lower verbal IQ scores and decreased visuomotor coordination. This finding suggested that moderate neonatal hyperbilirubinemia may have precipitated an increased sensitivity to subsequent exposure to lead.