Related Experiment Video
Updated: Aug 24, 2026
Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
Published on: March 6, 2018
Neurodevelopmental effects of postnatal lead exposure at very low levels
Lisa M Chiodo1, Sandra W Jacobson, Joseph L Jacobson
1Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Room 460, 2751 E. Jefferson, Detroit, MI 48207, USA. lchiodo@med.wayne.edu
Insights
Even low blood lead levels in children are linked to neurobehavioral deficits. This study found no safe threshold for lead exposure, impacting intelligence, attention, and motor skills.
Area of Science:
- Environmental Health
- Neuroscience
- Pediatrics
Background:
- Lead exposure in children is a significant public health concern.
- Previous research suggests potential neurodevelopmental impacts, but the existence of a safe threshold for low-level exposure remains debated.
Purpose of the Study:
- To investigate specific neurobehavioral deficits in children exposed to very low blood lead levels.
- To systematically analyze the dose-response relationship and identify any potential threshold for lead exposure effects.
Main Methods:
- A cohort of 246 inner-city African American children had blood lead concentrations measured at 7.5 years of age.
- Neurobehavioral assessments included intelligence, reaction time, visual-motor integration, fine motor skills, attention, executive function, and behavioral observations.
- Nonparametric regression and dichotomized regression analyses were used to examine lead levels and outcomes.
Main Results:
- Neurobehavioral deficits were consistently observed in relation to low blood lead levels.
- Affected domains included intelligence, reaction time, visual-motor integration, fine motor skills, attention, executive function, off-task behaviors, and withdrawn behaviors.
- A gradual, linear dose-response relationship was suggested, with no evidence of a threshold discontinuity, even at levels as low as 3 microg/dl.
Conclusions:
- There is no apparent lower bound threshold for adverse neurobehavioral effects of postnatal lead exposure.
- Low-level lead exposure is associated with a wide range of neurodevelopmental and behavioral deficits in children.
- Findings support the need for stringent policies to minimize all lead exposures in children.
Abstract:
This study is among the first to examine specific neurobehavioral deficits in children exposed at very low lead levels. A systematic analysis for the presence of a threshold of lead exposure was conducted. The sample consisted of 246 African American, inner-city children from whom blood lead concentrations were assessed at 7.5 years of age. The results consistently show neurobehavioral deficits in relation to low levels of lead in the areas of intelligence, reaction time, visual-motor integration, fine motor skills, attention, including executive function, off-task behaviors, and teacher-reported withdrawn behaviors. Effects were identified in the specific domains of attention, executive function, visual-motor integration, social behavior, and motor skills, which have been previously suggested as part of lead's "behavioral signature". Visual inspection of nonparametric regression plots suggested a gradual linear dose-response relation for most endpoints. No threshold discontinuity was evident. Regression analyses in which lead exposure was dichotomized at 10 microg/dl were no more likely to be significant than analyses dichotomizing exposure at 5 microg/dl. Given that associations were found between lead levels as low as 3 microg/dl for multiple outcomes, these data provide additional evidence that there is no apparent lower bound threshold for postnatal lead exposure.
Related Concept Videos
01:07Teratogenicity
01:30Attention-Deficit/Hyperactivity Disorder
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.
01:30Neurulation