Blood lead, bone lead and child attention-deficit-hyperactivity-disorder-like behavior

Sci Total Environ. 2019 Apr 1:659:161-167. doi: 10.1016/j.scitotenv.2018.12.219. Epub 2018 Dec 15.

Abstract

Background and objective: Mounting evidence showed that lead exposure increased the risk of child attention-deficit-hyperactivity disorder (ADHD). Epidemiologic studies have typically used the blood-lead as a biomarker of lead exposure; blood-lead levels mostly reflect recent lead exposure. However, few studies have examined the relationship between bone-lead, a biomarker of cumulative exposure, and ADHD. Therefore, we aimed to compare the associations of bone-lead vs blood-lead levels with child ADHD symptoms and comorbidities.

Methods: A total of 164 children aged 3-15 years were enrolled during 2014-2015. The Vanderbilt-ADHD-Diagnostic-Parent-Rating Scale (VADPRS) was used to evaluate the children's ADHD symptoms and comorbidities. Children's blood and bone lead concentrations were assessed, the latter using a non-invasive K-X-ray-fluorescence technique. According to blood-lead levels, children were classified into high (blood-lead ≥ 10.0 μg/dL) and low (blood-lead < 10.0 μg/dL) blood-lead groups. According to bone-lead levels, children were classified into high (bone-lead ≥ 2.66 μg/g) and low (bone-lead < 2.66 μg/g) bone-lead groups. We associated blood/bone lead with VADPRS data using multi-variable binary logistic regression models.

Results: Children in the high blood-lead group had higher hyperactivity/impulsivity (P = 0.02) scores than the corresponding low blood-lead group. Children in the high bone-lead group had higher hyperactivity/impulsivity (P = 0.02) and oppositional-defiant-disorder (ODD) (P = 0.03) scores than the corresponding low bone-lead group. After adjusting for relevant confounders, children in the high bone-lead group were more likely to have ODD-behavior than the low group (OR = 6.7, 95%CI: 1.2-36.5). However, no adjusted association was observed between blood-lead and any ADHD-domain score.

Conclusion: High levels of cumulative lead exposure in children may be an independent risk factor of ODD-behavior.

Keywords: ADHD; Blood; Bone; Lead; ODD.

MeSH terms

  • Adolescent
  • Attention Deficit Disorder with Hyperactivity / chemically induced
  • Attention Deficit Disorder with Hyperactivity / epidemiology*
  • Child
  • Child, Preschool
  • China / epidemiology
  • Comorbidity*
  • Female
  • Humans
  • Lead / blood*
  • Male
  • Tibia / chemistry*

Substances

  • Lead