Low levels of lead exposure increases anxiety and depression in children, according to a study published in JAMA Pediatrics. Prior studies have shown lead's other effects, like lowering IQ, triggering aggression, and causing other permanent behavioral and cognitive problems. This new study sought to establish the internalized emotional disorders that children, who are exposed to lead, might feel.

Though the US has lowered its lead action level to 5.0 micrograms per deciliter of blood for children, the effects of lead exposure are still visible. In China, where the experiment was conducted, the lead action level for children is 10.0 micrograms per deciliter.

The Research

Participants in this study were 1,341 children in Jitan, China, who were between three and five years old. The children had a mean lead exposure level of 6.4 micrograms per deciliter. Researchers used the Chinese versions of the Child Behavior Checklist and Caregiver-Teacher Report to measure behavioral issues. The reports were issued when each child was six years old.

Results showed a significant association between the concentration of lead in blood and teacher-reported behavioral problems. Children with higher levels of lead in their blood were more likely to have emotional difficulties and pervasive developmental issues. Teachers and parents also reported more “internalizing problems" in children with higher lead exposure, like anxiety and depression. Even children with the mean concentration of lead in their systems had behavioral problems.

What It Means

Though entirely preventable, lead poisoning accounts for about .6% of the global burden of disease, according to the World Health Organization. According to the American Academy of Pediatrics Committee on Environmental Health, children are at a greater risk of lead exposure than adults. At a rate of 10 micrograms per deciliter, the acceptable amount in China and many other countries, children could experience:

  • Decreased IQ levels
  • Decreased hearing capabilities
  • Decreased growth rates
  • Impaired peripheral nerve function
  • Transplacental Transfer

This study confirmed that anxiety and depression are two additional side effects of lead exposure. While there are no guarantees that lead exposure is the only cause of anxiety and depression in children, it should be considered a contributing factor. In the future, countries should consider lowering acceptable lead exposure levels for children to improve both physical and mental health in their population.

Date of original publication: .


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Jianghong Liu, PhD; Xianchen Liu, MD, PhD; Wei Wang, PhD; Linda McCauley, PhD; Jennifer Pinto-Martin, PhD; Yingjie Wang, MS; Linda Li, BA; Chonghuai Yan, PhD; Walter J. Rogan, MD. Blood Lead Concentrations and Children's Behavioral and Emotional Problems: A Cohort Study. JAMA Pediatrics; DOI: 10.1001/jamapediatrics.2014.332