Low-level lead exposure in childhood influences neuropsychological performance.

Cumulative lead exposure in 193 inner-city black children was assessed by measuring lead concentrations in the primary and circumpulpal dentine of their deciduous teeth. Lead concentrations for these children were comparable to the concentrations reported in population studies of low-income children living in inner-city areas. Analysis of the children's neuropsychological test performance showed that elevated lead levels were associated with deficits in visual-motor functioning and perceptual integration, right-left orientation, and verbal abstraction; other verbal abilities and motor functioning were not affected. Possible alternative explanations for these findings were evaluated by examining the relationships between lead and maternal intelligence, family socioeconomic status, and perinatal indicators of neurological impairment. None of these relationships was significant. It was concluded that, even at levels usually regarded as asymptomatic, lead in the environment represents a hazard to inner-city children.