Neuropsychological function in children with blood lead levels <10 microg/dL

Area of Science:

• Environmental Health
• Pediatric Neurodevelopment
• Toxicology

Background:

• Established adverse effects of high blood lead levels (BLLs) in children (> or = 10 microg/dL).
• Need to clarify cognitive effects of BLLs below 10 microg/dL, prevalent in the US population.

Purpose of the Study:

• To evaluate the association between BLLs < 10 microg/dL and various cognitive abilities in children.
• To identify specific cognitive domains affected by low-level lead exposure.

Main Methods:

• Analysis of data from 534 children aged 6-10 enrolled in the New England Children's Amalgam Trial (NECAT).
• Statistical adjustment for covariates including age, race, socioeconomic status, and primary caregiver IQ.
• Assessment of cognitive abilities using IQ scores, Wechsler Individual Achievement Test (WIAT), and measures of attention and working memory.

Main Results:

• Children with BLLs of 5-10 microg/dL showed significantly lower IQ scores (5.0 points) compared to those with BLLs of 1-2 microg/dL.
• Negative associations were observed between BLLs of 5-10 microg/dL and WIAT scores, with deficits in reading (7.8 points) and math (6.9 points).
• Low-level lead exposure was linked to decreased attention, working memory, spatial attention, and executive function, with academic achievement deficits persisting even after IQ adjustment.

Conclusions:

• Children's BLLs below 10 microg/dL are associated with compromised cognitive function.
• Cognitive deficits, particularly in academic achievement, attention, and executive function, are evident at BLLs of 5-10 microg/dL.
• Findings underscore the importance of minimizing lead exposure in children to protect cognitive development and academic success.