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Intellectual impairment in children exposed to polychlorinated biphenyls in utero
1Department of Psychology, Wayne State University, Detroit, MI 48202, USA.
Insights
Prenatal exposure to polychlorinated biphenyls (PCBs) can negatively impact children's intellectual function and reading skills long-term. Even slightly elevated PCB levels can lead to lower IQ scores and developmental delays.
Area of Science:
- Environmental Health
- Neurodevelopmental Toxicology
- Pediatric Health
Background:
- Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants.
- In utero PCB exposure is linked to adverse neurologic and intellectual effects in early childhood.
- Long-term neurodevelopmental effects of PCBs through school age require further investigation.
Purpose of the Study:
- To assess if prenatal PCB exposure effects persist through school age.
- To examine the impact of prenatal PCB exposure on reading and arithmetic skills acquisition.
Main Methods:
- A cohort of 212 children, recruited at birth, was studied.
- Children were tested at 11 years of age using IQ and achievement tests.
- Prenatal PCB exposure was measured using maternal serum, milk, and cord serum concentrations.
Main Results:
- Prenatal PCB exposure was associated with lower full-scale and verbal IQ scores (P = 0.02).
- Strongest effects were observed in memory and attention.
- Highly exposed children were more likely to have low average IQ scores and reading comprehension deficits.
Conclusions:
- In utero PCB exposure, even at slightly elevated levels, has a lasting impact on intellectual function.
- The developing fetal brain appears particularly sensitive to PCB exposure.
- Transplacental exposure, not breastfeeding, was linked to cognitive deficits.
Background:
In utero exposure to polychlorinated biphenyls, a ubiquitous environmental contaminant, has been linked to adverse effects on neurologic and intellectual function in infants and young children. We assessed whether these effects persist through school age and examined their importance in the acquisition of reading and arithmetic skills.
Methods:
We tested 212 children, recruited as newborns to overrepresent infants born to women who had eaten Lake Michigan fish contaminated with polychlorinated biphenyls. A battery of IQ and achievement tests was administered when the children were 11 years of age. Concentrations of polychlorinated biphenyls in maternal serum and milk at delivery were slightly higher than in the general population. A composite measure of prenatal exposure was derived from concentrations in umbilical-cord serum and maternal serum and milk.
Results:
Prenatal exposure to polychlorinated biphenyls was associated with lower full-scale and verbal IQ scores after control for potential confounding variables such as socioeconomic status (P = 0.02). The strongest effects related to memory and attention. The most highly exposed children were three times as likely to have low average IQ scores (P <0.001) and twice as likely to be at least two years behind in reading comprehension (P = 0.03). Although larger quantities of polychlorinated biphenyls are transferred by breast-feeding than in utero, there were deficits only in associated with transplacental exposure, suggesting that the developing fetal brain is particularly sensitive to these compounds.
Conclusions:
In utero exposure to polychlorinated biphenyls in concentrations slightly higher than those in the general population can have a long-term impact on intellectual function.