Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 123 (3), 271-6

Environmental Lead Exposure and Attention Deficit/Hyperactivity Disorder Symptom Domains in a Community Sample of South Korean School-Age Children


Environmental Lead Exposure and Attention Deficit/Hyperactivity Disorder Symptom Domains in a Community Sample of South Korean School-Age Children

Soon-Beom Hong et al. Environ Health Perspect.


Background: Low-level environmental exposure to lead has been associated with both reduced intelligence and symptoms of attention deficit/hyperactivity disorder (ADHD). However, few studies have estimated the association of lead and intelligence independent of ADHD, and it is not clear from previous studies whether lead is associated with both inattention and impulsivity ADHD symptoms.

Objectives: We estimated mutually adjusted associations of environmental lead exposure with both intelligence and ADHD symptoms, and associations between lead and specific ADHD-related domains.

Methods: Blood lead concentrations were measured in a general population of 1,001 children 8-11 years of age. We used multivariable linear regression models to estimate associations of blood lead concentrations with IQ scores, teacher and parent ratings of ADHD symptoms, and measures of inattention and impulsivity. Models were adjusted for demographic variables and other environmental exposures (blood levels of mercury and manganese, urinary concentrations of cotinine, phthalate metabolites, and bisphenol A).

Results: Associations of blood lead with lower IQ and higher impulsivity were robust to adjustment for a variety of covariates. When adjusted for demographic characteristics, other environmental exposures, and ADHD symptoms or IQ, a 10-fold increase in blood lead concentration was associated with lower Full-Scale IQ (-7.23; 95% CI: -13.39, -1.07) and higher parent- and teacher-rated hyperactivity/impulsivity scores (ADHD Rating Scale, 1.99; 95% CI: 0.17, 3.81 and 3.66; 95% CI: 1.18, 6.13, respectively) and commission errors (Continuous Performance Test, 12.27; 95% CI: -0.08, 24.62). Blood lead was not significantly associated with inattention in adjusted models.

Conclusions: Low-level lead exposure was adversely associated with intelligence in school-age children independent of ADHD, and environmental lead exposure was selectively associated with impulsivity among the clinical features of ADHD.

Conflict of interest statement

The authors declare they have no actual or potential competing financial interests.

Similar articles

See all similar articles

Cited by 17 PubMed Central articles

See all "Cited by" articles


    1. American Psychiatric Association. Washington, DC: American Psychiatric Association; 2000. Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR® (4th ed, text revision)
    1. Biederman J, Fried R, Petty CR, Wozniak J, Doyle AE, Henin A, et al. Cognitive development in adults with attention-deficit/hyperactivity disorder: a controlled study in medication-naive adults across the adult life cycle. J Clin Psychiatry. 2011;72(1):11–16. - PubMed
    1. Bouchard MF, Bellinger DC, Wright RO, Weisskopf MG. Attention-deficit/hyperactivity disorder and urinary metabolites of organophosphate pesticides. Pediatrics. 2010;125(6):e1270–e1277. - PMC - PubMed
    1. Bouchard M, Laforest F, Vandelac L, Bellinger D, Mergler D. 2007Hair manganese and hyperactive behaviors: pilot study of school-age children exposed through tap water. Environ Health Perspect 115122–127.; 10.1289/ehp.9504 - DOI - PMC - PubMed
    1. Braun JM, Froehlich TE, Daniels JL, Dietrich KN, Hornung R, Auinger P, et al. 2008Association of environmental toxicants and conduct disorder in U.S. children: NHANES 2001–2004. Environ Health Perspect 116956–962.; 10.1289/ehp.11177 - DOI - PMC - PubMed

MeSH terms