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LOW-DOSE LEAD POISONING IN CHILDHOOD PRODUCES LASTING COGNITIVE IMPAIRMENT.

Needleman and colleagues report the latest findings from their landmark study of lead poisoning, and the news is sobering. Between 1975 and 1978 they studied lead levels in shed primary teeth and performed extensive neurobehavioral testing in a randomly selected a group of 270 children in first and second grade.

In 1979, the study group reported that children with higher dentin lead levels were cognitively impaired. In the current report, they find that this impairment persists as the children approach adulthood. When children with the highest dentin lead levels (greater than 20 ppm) were compared to those with the lowest levels (less than 10 ppm), they were found to have a 7-fold greater risk of dropping out of high school, a 6-fold greater risk of having a reading disability, and significantly higher risks for low class standing, absenteeism, poor eye-hand coordination, and longer reaction times. Only a minority of the children with the highest dentin lead levels had experienced clinically evident lead poisoning, a disturbing finding.

This study demonstrates that low-level lead poisoning may produce lasting cognitive impairment, but it does not directly address the magnitude of the problem in the U.S.

— ALK

Published in Journal Watch General Medicine January 16, 1990

Citation(s):

Needleman HL et al. The long-term effects of exposure to low doses of lead in childhood: an 11-year follow-up report. N Engl J Med 1990 Jan 11 322 83-88.

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