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: F₂–8α 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 log₂-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. Log₂-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.

氧化应激（OS）是接触有毒金属的重要结果，但目前尚不清楚低水平的金属暴露对儿童OS的影响程度。我们检查了尿中砷（As），镉（Cd）和铅（Pb）浓度与OS的尿液标记物F ₂之间的横断面关联–8α异前列腺素和8-羟基-2-脱氧鸟苷（8-OHdG）。我们还测试了饮食摄入对效果的改善。在蒙得维的亚（Montevideo）的211名6-8岁儿童中，由于他们具有至少一种通过ELISA测得的OS标记，因此有资格参加研究，其中143例包括在完整病例分析中。尿中金属的测定采用电感耦合等离子体质谱法（ICP-MS：Pb，Cd），高效液相色谱在线检测氢化物产生的ICP-MS（As-代谢物）；浓度为log ₂-转换。调整所有尿液标记物的尿比重。进行了两次24小时饮食召回，以估计儿童的饮食摄入量，包括水果和蔬菜的总摄入量以及维生素C，锌和纤维的摄入量。使用普通最小二乘（OLS）和加权分位数和（WQS）回归来估计金属与每个OS标记物之间的关联作为结果。金属暴露通常很低：尿中砷，镉，铅的中位数分别为9.6μg/ L，0.06μg/ L和1.9μg/ L。8-异前列腺素的中位数浓度为1.1，而8-OHdG的中位数浓度为39.6 ng / mL。日志₂在协变量调整的OLS模型中，尿中As的浓度与8-OHdG的浓度呈正相关（10.90 [3.82，17.97]），该模型还考虑了Cd和Pb的暴露。在WQS中，混合指数也与较高的8-OHdG相关（指数值每增加25％，则为8.71 [1.12，16.3]），这主要是由砷暴露引起的。几乎没有证据表明饮食中的抗氧化剂可以改善效果。总而言之，即使在低水平下，砷暴露也与可检测到的DNA氧化损伤有关。