August 18, 1993

Declining Blood Lead Levels and Cognitive Change in Children-Reply

Author Affiliations

Albert Einstein College of Medicine Bronx, NY

JAMA. 1993;270(7):828-829. doi:10.1001/jama.1993.03510070049022

In Reply.  —We appreciate the thoughtful comments on our article in JAMA and agree with those who urge caution in interpreting the results. Our study was the first large-scale, systematic attempt to address the consequences of intervention with moderately lead-poisoned children; it thus represents only the first step in accumulating data relevant to the issue of reversibility. The interesting Chinese study reported by Dr Rabinowitz adds to that effort.We shared Dr Ernhart's concern about the lack of relationship between blood lead levels and CIs at the initial time point. As we noted, however, both the initial effects of low to moderate levels of lead and the reversibility of those effects are likely to be part of a cumulative process, not always evident at single time points. The analyses of change, although difficult, may be the only way to investigate such dynamic processes.Ernhart rightly underscored the failure to find