Bone lead levels and delinquent behavior.
Level 3 - non-randomized controlled study
Retrospective cohort study assessing behavioral outcomes across childhood by bone lead level.
What was done
A retrospective cohort study assessed the association between body lead burden and social adjustment. From 850 first-grade boys in public schools, 503 were selected using an antisocial behavior risk scale (all boys in the top 30th percentile matched with an equal number randomly chosen from the lower 70%). Of these, 301 boys participated. Cumulative lead exposure was assessed via K x-ray fluorescence spectroscopy of the tibia at age 12 years. Behavior was evaluated at ages 7 and 11 years using the Child Behavior Checklist (CBCL) completed by parents and teachers, alongside subject self-reports of antisocial and delinquent behavior. Evaluators and subjects were blind to bone lead measurements.
What was found
No exact numerical values, effect sizes, or confidence intervals were reported in the abstract. At age 7, borderline associations were observed between lead levels and teacher-rated aggression, delinquency, and externalizing scores after covariate adjustment. At age 11, higher bone lead was significantly associated with parent-reported somatic complaints, delinquent, aggressive, internalizing, and externalizing behaviors, and teacher-reported somatic complaints, anxious/depressed behavior, social problems, attention problems, delinquency, aggression, and internalizing/externalizing behaviors. High-lead subjects had significantly higher self-reported delinquency at age 11, showed worse trajectories on all CBCL items over the 4-year period, and had an increased risk of exceeding clinical thresholds (T > 70) for attention, aggression, and delinquency.
Why it matters
This study links cumulative skeletal lead burden to emergent and worsening aggressive and delinquent behaviors over childhood, using objective bone lead measurements and multi-informant reporting.
Limits
The abstract does not provide numerical effect estimates, exposure concentrations, p-values, or confidence intervals. The sample was restricted to boys, limiting generalizability to females. Only 301 of 503 invited subjects enrolled, introducing potential participation bias, and unmeasured confounding cannot be ruled out.
Cited by
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