Lead is a known neurotoxic metal, and child externalizing behavior (aggression, ADHD, and oppositional disorder) has been identified as a risk factor for adolescent delinquency and later adult violence. There is preliminary evidence that even at sub- clinical lead exposure levels, children experence negative cognitive and behavioral outcomes. However, it is still unclear whether such effects are sustained or how the pathogenesis of the effect of sub-clinical lead exposure is shaped. Based on the evidence from our preliminary analyses in a longitudinal cohort study, we propose to study the mediating mechanisms by which exposure to lead during the preschool years contribute to externalizing behavior in early adolescence. Lead exposure is hypothesized to give rise to two related symptoms, cognitive impairment (low IQ, reduced P300 event- related potentials, poor school performance) and emotion dysregulation (low vagal tone, low arousal, and low stress reactivity) which in turn form the mechanistic pathway to childhood externalizing behavior. This new R01 builds on the PI's current NIEHS-funded K award and unique data from an on-going large prospective cohort study. The initial epidemiological sample consisted of 1,650 3-5 year-old Chinese boys and girls whose blood lead levels were obtained in 2004, and their IQ test scores and behavioral measures were assessed at age 6 years. We propose to add new neurocognitive and emotion measures in addition to repeating measures of blood lead, IQ, behavior, school performance, and psychosocial risk factors during preadolescent years (estimate N =1,200). Structural equation modeling will be used to test the main effect, interactive and mediating effects of early lead exposure on later externalizing behavior. The interdisciplinary research team has decades of experience in studying lead exposure, child behavior problems, psychophysiology, and child mental health. Findings have potential theoretical and clinical implications for understanding the symptoms of neurocognitive and emotional effects of lead exposure on children's externalizing behavior. By integrating neuroscience assessment tools with epidemiology and toxicology, this study could potentially inform strategies for lowing current CDC-defined safe lead levels, and reduce the likelihood of neurocognitive deficits and behavior problems. Ultimately it will potentially minimize the impact of negative environmental exposures on children's mental health, thus improving their subsequent well-being over the life-course.

Public Health Relevance

Understanding the neurobiological basis of lead exposure on children's externalizing behavior will be significant to future attempts to tackle two important global public health issues: lead exposure and children externalizing behavior, ultimately helping to improve the quality life of the individual and the family unit.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Research Project (R01)
Project #
5R01ES018858-04
Application #
8461618
Study Section
Child Psychopathology and Developmental Disabilities Study Section (CPDD)
Program Officer
Gray, Kimberly A
Project Start
2010-09-08
Project End
2015-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
4
Fiscal Year
2013
Total Cost
$336,698
Indirect Cost
$118,403
Name
University of Pennsylvania
Department
Other Health Professions
Type
Schools of Nursing
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Liu, Jianghong; Hanlon, Alexandra; Ma, Chenjuan et al. (2014) Low blood zinc, iron, and other sociodemographic factors associated with behavior problems in preschoolers. Nutrients 6:530-45
Liu, Jianghong; Liu, Xianchen; Wang, Wei et al. (2014) Blood lead concentrations and children's behavioral and emotional problems: a cohort study. JAMA Pediatr 168:737-45
Liu, Jianghong; Leung, Patrick; Yang, Amy (2014) Breastfeeding and active bonding protects against children's internalizing behavior problems. Nutrients 6:76-89
Liu, Jianghong; Li, Linda; Wang, Yingjie et al. (2013) Impact of low blood lead concentrations on IQ and school performance in Chinese children. PLoS One 8:e65230
Li, Linda; Liu, Jianghong (2013) The effect of pediatric traumatic brain injury on behavioral outcomes: a systematic review. Dev Med Child Neurol 55:37-45
Liu, Jianghong; Lynn, Richard (2013) An Increase of Intelligence in China 1986-2012. Intelligence 41:
Liu, Jianghong; Hwang, Wei-Ting; Dickerman, Barbra et al. (2013) Regular breakfast consumption is associated with increased IQ in kindergarten children. Early Hum Dev 89:257-62
Liu, Jianghong; Li, Linda (2013) Parent-reported mild head injury history and behavioural performance in children at 6 years. Brain Inj 27:1263-70
Liu, Jianghong; Leung, Patrick W L; McCauley, Linda et al. (2013) Mother's environmental tobacco smoke exposure during pregnancy and externalizing behavior problems in children. Neurotoxicology 34:167-74
Liu, Jianghong; Zhou, Guoping; Wang, Yingjie et al. (2012) Sleep problems, fatigue, and cognitive performance in Chinese kindergarten children. J Pediatr 161:520-525.e2

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