The effect of lead exposure on behavior problems in preschool children

Objectives. Interpreting associations between lead exposure and child behavior problems is difficult because studies have not controlled for sociodemographic confounders or have used shed teeth to mark exposure. This study explored associations between blood lead and preschool behavior. Methods. Children from a smelter town and a non-lead-exposed town in Yugoslavia were followed up prospectively from pregnancy through age 3. The Child Behavior Checklist was used to assess behavior problems in 379 3-year- olds, controlling for sociodemographic factors and difficult infant temperament. Results. Multiple regression revealed the expected significant associations between checklist subscales and sociodemographic factors, which explained 7% to 18% of the variance on the subscales. Concurrent blood lead explained a significant 1% to 4% of the variance on the Destructive and Withdrawn subscales. Earlier difficult temperament explained an additional 2% to 5% of the checklist variance. Scores on the Destructive subscale were consistently associated with blood lead. As blood lead increased from 10 to 20 μg/dL, subscale scores increased by approximately 0.5 points. Conclusions. Lead/behavior associations are significant but small compared with the effects of social factors.