A study by Children’s Hospital Los Angeles has shown that the risk of lead exposure is linked to decreased brain volume in adolescents. The study involved nearly 10,000 adolescents and revealed a relationship between lead exposure risk and brain structure in lower-income families.
Though leaded gas and lead-based paint were banned decades ago, the risk of lead exposure is far from gone, according to the study. Led by Dr. Elizabeth Sowell, the study shows that living in neighborhoods with high risk of lead exposure is associated with differences in brain structure and cognitive performance in some children. Her findings, published by Nature Medicine, also show a deeper trend that children in lower-income families may be at increased risk.
Sowell and her team at the Saban Research Institute of Children’s Hospital Los Angeles hypothesized that children in lower-income families could be particularly vulnerable to the effects of living in high lead-risk environments. Sowell’s laboratory is part of the Adolescent Brain Cognitive Development Study, which has enrolled nearly 12,000 children from 21 sites throughout the United States. ABCD follows participants from the age of 9 and10 into adulthood, collecting health and brain development information.
The study determined that an increased risk of lead exposure is associated with decreases in cognitive performance and in the surface area and volume of the cortex – the surface of the brain responsible for initiating conscious thought and action. The result was not true for children from mid- or high-income families.
“We were interested in how lead exposure influences brain anatomy and function,” added Andrew Marshall, a postdoctoral research fellow in Sowell’s lab. “What we’re seeing here is that there are more pronounced relationships between brain structure and cognition when individuals are exposed to challenges like low income or risk of lead exposure.”
The ABCD study has not yet examined blood lead levels in the children, but the authors showed that risk of lead exposure is predictive of blood lead levels. Further studies are needed to determine the precise cause for the differences, such as whether lead exposure itself or other factors associated with living in a high lead-risk environment is contributing to the problem.
Sowell’s goal is to promote awareness of how environmental toxins affect children, and she emphasized that income and risk of lead exposure do not define a child.
“It’s absolutely not a foregone conclusion that these risks make you less intellectually capable,” Sowell said. “Many children who live in low-income, high-risk areas will be successful. The take home point is that this can be fixed. Lead does not have to be in the environment. We can remove it and really help kids get healthier.”
For information, visit chla.usc.edu.
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