The relationship of hyperactivity to moderately elevated lead levels.

Controversy exists with respect to whether moderately elevated lead levels are toxic in certain children with various central nervous system dysfunctions. One way of addressing this controversy is to remove the lead; if the condition is ameliorated a presumption of toxicity becomes reasonable. Such a strategy is reported herein. Children with an operationally defined central nervous system dysfunction (hyperactivity) and moderately elevated lead levels were treated with a lead chelating agent in a random allocation double blind treatment regimen. The finding of statistically significant and obvious behavioral improvement reported by three separate evaluators (i.e., parent, teacher, and treating physician) of the child suggests that the presumption of a toxic relationship between moderately elevated lead levels and hyperactivity is supported.