Relationship between lead exposure indicators and neuropsychological performance in children

This study surveyed 237 schoolchildren in a lead-polluted industrial area in northern Italy to assess the relationship between various biological indicators (lead in blood, hair and teeth, and delta-aminolevulinic dehydratase [ALA-D] activity) and some neuropsychological functions, assessed by a battery of five psychometric tests. The geometric means of lead measured in blood, hair and teeth were 10.99 micrograms/dl, 6.79 micrograms/g and 6.05 micrograms/g, respectively. Mean ALA-D activity was 51 mU/ml RBC. By analysis of covariance, after regressing out the variance accountable to confounding variables (age, sex, occupation/education of parents), Total and Verbal WISC-R IQ and Toulouse Pieron test results were significantly affected by the levels of lead in teeth. ALA-D values also appeared to be related to WISC-R IQ results (Total, Verbal and Performance).