Childhood lead poisoning.

Substantial changes in the toxicology and epidemiology of lead have resulted in revisions in the definition of toxicity, and have altered estimates of the numbers of children at risk. As observational studies have increased their sample size, improved the sensitivity of their measurements, and polished epidemiological designs, concentrations of lead once thought to be harmless have been shown to have deleterious neurobehavioral consequences. Prevalence rates have changed in correspondence. Public policy has shifted from case finding to emphasizing primary prevention, the only appropriate strategy for this group of children. It is possible that the rate of the disease could be driven close to zero within two decades.