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Lead exposure, IQ, and behavior in urban 5- to 7-year-olds: does lead affect behavior only by lowering IQ?
- Source :
-
Pediatrics [Pediatrics] 2007 Mar; Vol. 119 (3), pp. e650-8. - Publication Year :
- 2007
-
Abstract
- Background: Lead exposure in childhood lowers IQ scores, but its effect on children's behavior is less clear. Because IQ, per se, affects behavior, measuring the direct effect of lead requires measuring and then adjusting for IQ. In addition, either peak blood lead concentration, usually at 2 years old, or the lower blood lead level measured at school age may be the most relevant. Few studies have all of this information.<br />Objectives: The purpose of this work was to differentiate the direct effect of lead on behavior and the indirect effect through IQ and to examine the strength of the association for peak and concurrent blood lead concentration.<br />Methods: Data come from a clinical trial of the chelating drug succimer to prevent cognitive impairment in 780 urban 12- to 33-month-olds with blood lead concentrations of 20 to 44 microg/dL. The children were followed from ages 2 to 7 years. The trial data were analyzed as a prospective observational study.<br />Results: Blood lead concentration at 2 years old was not associated with Conners' Parent Rating Scale-Revised scores at 5 years of age or Behavioral Assessment Systems for Children scores at 7 years of age. Blood lead level at 7 years of age had direct effects on the Behavioral Assessment Systems for Children behavioral symptoms index, externalizing, and school problems at age 7.<br />Conclusions: Concurrent blood lead concentration was associated with externalizing and school problems scales at 7 years of age, and the effect was not entirely mediated through the effect of lead on IQ.
- Subjects :
- Age Distribution
Causality
Chelating Agents therapeutic use
Child
Child Behavior Disorders diagnosis
Child Behavior Disorders prevention & control
Child, Preschool
Cognition Disorders diagnosis
Cognition Disorders prevention & control
Comorbidity
Epidemiological Monitoring
Female
Follow-Up Studies
Humans
Intelligence
Lead blood
Lead toxicity
Lead Poisoning, Nervous System, Childhood blood
Lead Poisoning, Nervous System, Childhood drug therapy
Male
Odds Ratio
Regression Analysis
Succimer therapeutic use
United States epidemiology
Urban Population
Child Behavior Disorders epidemiology
Cognition Disorders epidemiology
Environmental Exposure statistics & numerical data
Environmental Monitoring statistics & numerical data
Lead Poisoning, Nervous System, Childhood epidemiology
Subjects
Details
- Language :
- English
- ISSN :
- 1098-4275
- Volume :
- 119
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Pediatrics
- Publication Type :
- Academic Journal
- Accession number :
- 17332184
- Full Text :
- https://doi.org/10.1542/peds.2006-1973