Blood lead levels, even below the permitted limit, are associated with poorer school performance in children
Lead exposure in children can affect their neurodevelopment. In the United States, the maximum blood concentration limit for this metal was lowered to 3.5 μg/dL (micrograms per decilitre) in 2021, down from 10 μg/dL in 2012. Now, a study has analysed data from more than 300,000 children in Iowa and found an association between higher concentrations and poorer school performance in reading and maths, even below the 3.5 μg/dL limit, prompting the researchers to reconsider this figure. The results are published in the journal JAMA Network Open.
Miguel Motas - plomo niños EN
Miguel Motas
Professor of Toxicology in the Department of Social and Health Sciences at the University of Murcia
What is your overall opinion of the study? Is it of good quality?
‘I think it is a good study with an interesting starting hypothesis, which it addresses with a large, representative sample size.’
How does it fit in with existing evidence and what new information does it provide?
"It casts doubt on existing evidence, suggesting the application of the precautionary principle that there are no safe levels of lead in children. It provides evidence that it is advisable to lower the acceptable blood lead level in young children, as levels below this acceptable level cause learning delays.‘
Are there any important limitations to consider?
’As this is a study using existing data, some relevant variables, such as family income and housing quality, were not measured."
Pablo Olmedo - plomo niños EN
Pablo Olmedo
Full professor in the Department of Forensic Medicine, Toxicology and Physical Anthropology, Faculty of Medicine
Lead is known to be a neurotoxic metal, especially in children. There is considerable evidence that early exposure to lead affects children's neurological development. There is no blood lead level that can be considered safe for children. Therefore, the results of this study do not surprise me.
George L. Wehby.
- Research article
- Peer reviewed
- Observational study
- People
