TY - JOUR
T1 - Prenatal and postnatal exposures to four metals mixture and IQ in 6-year-old children
T2 - A prospective cohort study in South Korea
AU - Lee, Kyung-Shin
AU - Kim, Kyoung-Nam
AU - Ahn, Yebin D
AU - Choi, Yoon-Jung
AU - Cho, Jinwoo
AU - Jang, Yoonyoung
AU - Lim, Youn-Hee
AU - Kim, Johanna Inhyang
AU - Shin, Choong Ho
AU - Lee, Young Ah
AU - Kim, Bung-Nyun
AU - Hong, Yun-Chul
N1 - Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.
PY - 2021
Y1 - 2021
N2 - BACKGROUND: Humans are exposed to a mixture of metals during their lifetime; however, evidence of neurotoxicity of such mixtures in critical time windows is still insufficient. We aimed to elucidate the associations of four metals mixture across multiple time points with children's intelligence quotient (IQ) in a prospective cohort study.METHODS: Prenatal exposure and exposure at age 4 and 6 years to four types of blood metals, namely lead, mercury, cadmium, and manganese were quantified in 502 pregnant women and their children who participated in the Environment and Development Cohort study. Children' s IQ scores were assessed using the Wechsler Intelligence Scale at age 6. Bayesian kernel machine regression (BKMR), quantile g-computation models, and elastic net (ENET) models were used to assess the associations of their blood metals mixture with IQ scores.RESULTS: Multivariate linear regression models indicated that postnatal blood manganese exposure at the age of 4 years was significantly negatively associated with children's IQ [β = - 5.99, 95% confidence interval (CI): -11.37 to - 0.61]. In the multi-chemical BKMR and quantile g-computation model, statistically significant inverse associations were found between the mixture of prenatal and postnatal metals and children's IQ score (Difference in children' IQ per quartile increase: -2.83; 95% CI: -5.28, -0.38). Interestingly, we found that manganese levels at both age of 4 and 6 years were contributing factors to children's IQ in the mixture models, namely, BKMR, quantile g-computation, and ENET models.CONCLUSIONS: Multi-pollutant mixtures of prenatal and postnatal exposures to four metals affected child IQ at 6 years of age. We found a relationship between manganese exposure at both age 4, and 6 years and children's IQ. Additional studies are warranted to confirm these associations and to control the exposure to different metals during pregnancy and preschool childhood.
AB - BACKGROUND: Humans are exposed to a mixture of metals during their lifetime; however, evidence of neurotoxicity of such mixtures in critical time windows is still insufficient. We aimed to elucidate the associations of four metals mixture across multiple time points with children's intelligence quotient (IQ) in a prospective cohort study.METHODS: Prenatal exposure and exposure at age 4 and 6 years to four types of blood metals, namely lead, mercury, cadmium, and manganese were quantified in 502 pregnant women and their children who participated in the Environment and Development Cohort study. Children' s IQ scores were assessed using the Wechsler Intelligence Scale at age 6. Bayesian kernel machine regression (BKMR), quantile g-computation models, and elastic net (ENET) models were used to assess the associations of their blood metals mixture with IQ scores.RESULTS: Multivariate linear regression models indicated that postnatal blood manganese exposure at the age of 4 years was significantly negatively associated with children's IQ [β = - 5.99, 95% confidence interval (CI): -11.37 to - 0.61]. In the multi-chemical BKMR and quantile g-computation model, statistically significant inverse associations were found between the mixture of prenatal and postnatal metals and children's IQ score (Difference in children' IQ per quartile increase: -2.83; 95% CI: -5.28, -0.38). Interestingly, we found that manganese levels at both age of 4 and 6 years were contributing factors to children's IQ in the mixture models, namely, BKMR, quantile g-computation, and ENET models.CONCLUSIONS: Multi-pollutant mixtures of prenatal and postnatal exposures to four metals affected child IQ at 6 years of age. We found a relationship between manganese exposure at both age 4, and 6 years and children's IQ. Additional studies are warranted to confirm these associations and to control the exposure to different metals during pregnancy and preschool childhood.
U2 - 10.1016/j.envint.2021.106798
DO - 10.1016/j.envint.2021.106798
M3 - Journal article
C2 - 34339957
VL - 157
JO - Environment international
JF - Environment international
SN - 0160-4120
M1 - 106798
ER -