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Assessment and Evaluation of the High Risk Neonate: The NICU Network Neurobehavioral Scale
Published on: August 25, 2014
Lead exposure and neurobehavioral development in later infancy
K N Dietrich1, P A Succop, R L Bornschein
1University of Cincinnati College of Medicine, Department of Environmental Health, OH 45267-0056.
Insights
Early lead exposure in infants showed temporary neurodevelopmental impacts. However, by age two, these effects on cognitive and motor skills appeared to resolve, suggesting a potential catch-up growth.
Area of Science:
- Environmental Health
- Neuroscience
- Developmental Pediatrics
Background:
- Lead exposure is a significant public health concern, particularly for pregnant women and infants.
- Prenatal and early postnatal periods are critical windows for neurodevelopment, making fetuses and infants vulnerable to environmental toxins.
- Understanding the long-term neurobehavioral consequences of early lead exposure is crucial for effective intervention strategies.
Purpose of the Study:
- To prospectively assess the neurobehavioral effects of fetal and postnatal lead exposure in infants during the first two years of life.
- To investigate the relationship between blood lead levels and neurodevelopmental outcomes using standardized assessments.
- To examine potential catch-up growth in neurobehavioral development following early lead exposure.
Main Methods:
- Prospective cohort study design.
- Measurement of maternal and infant blood lead levels at multiple time points (prenatal, quarterly from birth to 2 years).
- Utilized Bayley Scales of Infant Development (Mental and Psychomotor) at 3, 6 months, and 2 years; employed multiple regression and structural equation modeling.
Main Results:
- Low mean prenatal blood lead levels (8.0 µg/dL), but 25% of infants had levels ≥25 µg/dL in the second year.
- Significant associations were found between prenatal/neonatal blood lead levels and lower Bayley scores at 3 and 6 months.
- No statistically significant neurobehavioral effects of lead exposure were detected by 2 years of age.
Conclusions:
- While early lead exposure (prenatal and neonatal) is associated with temporary deficits in infant neurodevelopment, these effects may not persist.
- Evidence suggests a potential for neurobehavioral catch-up growth in infants exposed to higher lead levels in utero, with recovery observed by age two.
- These findings highlight the importance of monitoring lead exposure and underscore the brain's potential resilience during early development.
Abstract:
A prospective methodology was used to assess the neurobehavioral effects of fetal and postnatal lead exposure during the first 2 years of life. Lead was measured in whole blood prenatally in mothers and at quarterly intervals in the infant. Prenatal blood lead levels were low (mean = 8.0 micrograms/dL). However, approximately 25% of the study infants had at least one serial blood lead level of 25 micrograms/dL or higher during the second year of life. Multiple regression and structural equation analyses revealed statistically significant relationships between prenatal and neonatal blood lead level and 3- and 6-month Bayley Mental and/or Psychomotor Development Index. However, by 2 years of age, no statistically significant effects of prenatal or postnatal lead exposure on neurobehavioral development could be detected. Data consistent with the hypothesis that a postnatal neurobehavioral growth catch-up occurred in infants exposed fetally to higher levels of lead are presented.
