Multiple-metal exposure, diet, and oxidative stress in Uruguayan school children

Katarzyna Kordas, Aditi Roy, Marie Vahter, Julia Ravenscroft, Nelly Mañay, Fabiana Peregalli, Gabriela Martínez, Elena I. Queirolo

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Oxidative stress (OS) is an important consequence of exposure to toxic metals but it is unclear to what extent low-level metal exposures contribute to OS in children. We examined the cross-sectional association between urinary concentrations of arsenic (As), cadmium (Cd), and lead (Pb) and urinary markers of OS: F 2 –8α isoprostane and 8-hydroxy-2-deoxy-guanosine (8-OHdG). We also tested effect modification by dietary intakes. Of the 211 children aged 6–8 years living in Montevideo who were eligible for the study because they had at least one OS marker measured via ELISA, 143 were included in a complete-case analysis. Urinary metals were measured with inductively coupled plasma mass spectrometry (ICP-MS: Pb, Cd) and high-performance liquid chromatography online with hydride generation ICP-MS (As-metabolites); concentrations were log 2 -transformed. All urinary markers were adjusted for specific gravity of urine. Two 24-h dietary recalls were conducted to estimate children's dietary intakes, including total fruit and vegetable consumption and vitamin C, zinc and fiber intake. Ordinary least square (OLS) and weighted quantile sum (WQS) regressions were used to estimate the association between metals and each OS marker as outcome. Metal exposure was generally low: median urinary As, Cd, Pb 9.6 μg/L, 0.06 μg/L and 1.9 μg/L, respectively. Median 8-isoprostane concentration was 1.1 and 8-OHdG 39.6 ng/mL. Log 2 -transformed urinary As concentrations were positively associated with 8-OHdG concentrations (10.90 [3.82, 17.97]) in covariate-adjusted OLS models which also took account of exposure to Cd and Pb. In WQS, a mixture index was also associated with higher 8-OHdG (8.71 [1.12, 16.3] for each 25% increase in index value), mostly driven by As exposure. There was little evidence of effect modification by dietary antioxidants. In sum, even at low-level, As exposure is associated with detectable oxidative damage to the DNA.

Original languageEnglish
Pages (from-to)507-515
Number of pages9
JournalEnvironmental Research
Volume166
DOIs
StatePublished - Oct 2018

Bibliographical note

Funding Information:
We would like to thank nurses Delminda Ribeiro and Graciela Yuane for their help with sample collection and processing, nutritionists Valentina Baccino, Elizabeth Barcia, Soledad Mangieri and Virginia Ocampo for assistance with dietary recalls, and Jing Nie for assistance with data analysis. This study was funded by the National Institutes of Environmental Health Sciences/Fogarty International Center ( 1R21 ES16523 , PI: Kordas and 1R21 ES019949 , PI: Kordas).

Publisher Copyright:
© 2018 Elsevier Inc.

Keywords

  • Arsenic
  • Child
  • Metals
  • Oxidative stress

ASJC Scopus subject areas

  • Biochemistry
  • Environmental Science (all)

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