April 17, 2003
Lead Concentration and Intellectual Impairment
The relation between lead concentrations below 10 µg per deciliter (0.483 µmol per liter) and intellectual impairment is not well understood. In this prospective study, an increase in the peak blood lead concentration from 1 to 10 µg per deciliter during several measurements in early life was associated with a 7.4-point reduction in IQ at the age of five years, after adjustment for maternal IQ and other potential confounders.
These data suggest that even a blood lead concentration below 10 µg per deciliter may adversely affect cognitive development, and they provide further support for the goal of primary prevention of lead exposure.