Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Mar;2022(181-182):53-66.
doi: 10.1002/cad.20458. Epub 2022 Apr 16.

Prenatal trace elements mixture is associated with learning deficits on a behavioral acquisition task among young children

Francheska M Merced-Nieves  1 , John Chelonis  2 , Ivan Pantic  3 , Lourdes Schnass  3 , Martha M Téllez-Rojo  4 , Joseph M Braun  5 , Merle G Paule  2 , Rosalind J Wright  1   6 , Robert O Wright  1   6 , Paul Curtin  1
Affiliations

Prenatal trace elements mixture is associated with learning deficits on a behavioral acquisition task among young children

Francheska M Merced-Nieves et al. New Dir Child Adolesc Dev. 2022 Mar.

Abstract

Children are exposed to many trace elements throughout their development. Given their ubiquity and potential to have effects on children's neurodevelopment, these exposures are a public health concern. This study sought to identify trace element mixture-associated deficits in learning behavior using operant testing in a prospective cohort. We included 322 participants aged 6-7 years recruited in Mexico City with complete data on prenatal trace elements measurements (third trimester blood lead and manganese levels, and & urine cadmium and arsenic levels), demographic covariates, and the Incremental Repeated Acquisition (IRA), an associative learning task. Weighted quantile sum (WQS) regression models were used to estimate the joint association of the mixture of all four trace elements and IRA performance. Performance was adversely impacted by the mixture, with different elements relating to different aspects of task performance suggesting that prenatal exposure to trace element mixtures yields a broad dysregulation of learning behavior.

Keywords: learning behavior; mixtures; prenatal; repeated acquisition; trace elements.

PubMed Disclaimer

Conflict of interest statement

Conflict of Interest

The authors declare no conflict of interest.

Figures

Figure 1.
Figure 1.
Diagram of the operant test panel. Starting at the top, there is a speaker and below are three circular press-plates. Below the circular press-plates, there are two different types of stimulus lights – correct and incorrect response indicator lights and serial position indicator lights (colored rectangles). At the bottom of the apparatus there is a container where nickels are delivered by a dispenser mounted inside the wooden cabinet. Illustration by Jill Gregory, used with permission of ©Mount Sinai Health System.
Figure 2.
Figure 2.
Diagram of third-link response during the Incremental Repeated Acquisition (IRA). Illustration by Jill Gregory, used with permission of ©Mount Sinai Health System.
Figure 3.
Figure 3.
Changes in IRA for a 1-quintile increase in the third trimester trace elements exposure Weighted Quantile Sum Index. Plotted points are beta coefficients, and lines are 95% confidence intervals for wqs and model covariates.
Figure 4.
Figure 4.
Weight uncertainty plots depicting weighted quantile sum mixture weights (y-axis) for each of 100 repeated holdout validation sets. Abbreviations: As = Arsenic, Cd = Cadmium, Mn = Manganese, and Pb = Lead. Notes: The pink lines indicate the concern threshold of 25% in 100 repeated holdouts. Data points indicate weights for each of the 100 holdouts. Box plots show 25th, 50th, and 75th percentiles, and whiskers show 10th and 90th percentiles of weights for the 100 holdouts. Closed diamonds show mean weights for the 100 holdouts.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Llop S, et al., Gender differences in the neurotoxicity of metals in children. Toxicology, 2013. 311(1–2): p. 3–12. - PubMed
    1. Merced-Nieves FM, et al., Metal mixtures and neurodevelopment: recent findings and emerging principles. Curr Opin Toxicol, 2021. 26: p. 28–32. - PMC - PubMed
    1. Carrico C, et al., Characterization of Weighted Quantile Sum Regression for Highly Correlated Data in a Risk Analysis Setting. J Agric Biol Environ Stat, 2015. 20(1): p. 100–120. - PMC - PubMed
    1. Bello GA, et al., Extending the Distributed Lag Model framework to handle chemical mixtures. Environ Res, 2017. 156: p. 253–264. - PMC - PubMed
    1. Tanner EM, Bornehag CG, and Gennings C, Repeated holdout validation for weighted quantile sum regression. MethodsX, 2019. 6: p. 2855–2860. - PMC - PubMed
-