Neuropsychological function in school-age children with low mercury exposures

Area of Science:

• Environmental Health
• Neuroscience
• Pediatrics

Background:

• The US EPA reference dose for methylmercury (MeHg) is based on high-exposure populations, with limited data on lower-level effects.
• Understanding MeHg's impact on US children's neurodevelopment is crucial due to potential dietary exposures.

Purpose of the Study:

• To investigate the association between hair mercury (Hg) levels and neuropsychological outcomes in US school-aged children.
• To evaluate potential non-linear relationships and identify critical exposure thresholds for adverse effects.

Main Methods:

• Utilized data from 355 children (ages 6-10) in the New England Children's Amalgam Trial.
• Collected hair Hg levels, sociodemographic data, and neuropsychological test scores.
• Employed linear and generalized additive models, controlling for covariates like fish consumption.

Main Results:

• No significant linear associations were found between hair Hg levels and neuropsychological test scores.
• Non-linear associations were observed for Math Reasoning and Visual-Motor Composite scores, with varied effects below 1.0 microg/g.
• Children with hair Hg levels < 1.0 microg/g did not show statistically significant adverse neuropsychological outcomes.

Conclusions:

• Hair Hg levels below 1.0 microg/g in US school-aged children are not associated with adverse neuropsychological function.
• Findings suggest current US exposure levels may not pose a significant neurodevelopmental risk.
• Further research on dose-response relationships at lower MeHg exposure levels is warranted.