The effects of bone lead poisoning on cognitive, achievement, attentional, and language functioning in children
Lead is the most widespread environmental neurotoxin in the United States. Exposure to lead in early childhood is extraordinarily common, especially among poor minority young children living in central cities. Lead poisoning has been found to cause many neuro-behavioral problems in children. Previous research has found relationships between lead poisoning found in blood and dentin and various factors such as IQ, achievement, behavior, memory and learning, reading disabilities, distractibility, and impulsivity. However, using blood lead concentrations and dentin lead concentrations to estimate lead exposure has its limitations. Blood lead has been found to measure recent exposure. Therefore, looking at blood to determine lead level can therefore be misleading. Dentin lead estimates suffer from other problems such as varying lead concentrations in different places in the same tooth and differences in lead concentrations among tooth types in the same mouth. In recent years, lead poisoning found in the bone has been identified as a good source to measure accumulated exposure.
The goal of this study is to determine whether increased body burden of lead, a sensitive and previously validated indicator of excess early lead exposure, is associated with cognitive, achievement, attentional, and language impairment in preadolescent urban youth.
Results of correlational analysis indicated no significant relationship between bone lead and cognitive, achievement, attentional, and language functioning. However, current blood levels were found to be significantly associated with hyperactivity (r = .35, p < .05) as measured by the Conners' Parent Rating Scales. As expected, bone lead and blood lead were negligibly correlated. No relationship was found between the covariate age and bone and blood levels. Modeled with previous research, the bone lead levels were divided into five groups testing for points of differentiation. Pairwise comparisons between bone levels and cognitive and achievement functioning showed no significant group differences. However, significant group differences were found on measures of attention as measured by the Conners' Parent and Teacher Rating Scales. While there were no significant group differences between bone levels and language functioning, moderate effect sizes, indicating possible differences given a larger sample size, were found on subtests, of the Clinical Evaluation of Language Fundamentals-Third Edition. Based on previous research, the Mann-Whitney U Analysis was used to compare low and high bone risk groups. (Abstract shortened by UMI.)
Families & family life;
0758: Cellular biology
0628: Families & family life
0628: Personal relationships