Temporal variability of urinary cadmium in spot urine samples and first morning voids.
Temporal variability of urinary cadmium in spot urine samples and first morning voids.
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DOI：
10.1038/jes.2016.28
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发表时间：
2017-05
影响因子：
4.5
通讯作者：
Meliker JR
中科院分区：
文献类型：
--
作者：
Vacchi-Suzzi C;Porucznik CA;Cox KJ;Zhao Y;Ahn H;Harrington JM;Levine KE;Demple B;Marsit CJ;Gonzalez A;Luft B;Meliker JR
镉是一种致癌的重金属。尿液中的镉水平被认为是长期身体负担的指标，因为镉在肾脏中积累，半衰期至少为10年。然而，尚未严格确定非职业接触人群尿液样本中生物标志物的时间稳定性。我们使用了重复测量尿镉（U-Cd）在现场尿液样本和第一次晨尿从两个单独的队列，以评估样品的时间稳定性。从两个队列，包括个人的两种性别的尿液样本进行了测量镉和肌酐。第一个队列（围产期暴露的家庭观察（HOPE））由21名从不吸烟者组成，他们提供了4份第一次晨尿样本，间隔2-5天，大约1个月后提供了一份额外的样本。第二个队列（世界贸易中心健康计划（WTC-HP））由78名个体组成，包括52名从不吸烟者，22名前吸烟者和4名当前吸烟者，他们平均间隔6个月提供2份现场尿液样本。计算来自每个个体的重复组的类内相关性以评估时间变异性。肌酐校正的U-Cd水平中位数（HOPE和WTC-HP分别为0.19和0.21 μg/g）与美国国家健康和营养检查调查记录的水平相似。组内相关性（ICC）很高（HOPE和WTC-HP分别为0.76和0.78），并且在队列之间相似，无论样本是间隔几天还是几个月采集的。在低暴露人群中，单点或第一次晨尿镉样本均显示出良好的重现性。
Cadmium is a carcinogenic heavy metal. Urinary levels of cadmium are considered to be an indicator of long-term body burden, as cadmium accumulates in the kidneys and has a half-life of at least 10 years. However, the temporal stability of the biomarker in urine samples from a non-occupationally exposed population has not been rigorously established. We used repeated measurements of urinary cadmium (U-Cd) in spot urine samples and first morning voids from two separate cohorts, to assess the temporal stability of the samples. Urine samples from two cohorts including individuals of both sexes were measured for cadmium and creatinine. The first cohort (Home Observation of Perinatal Exposure (HOPE)) consisted of 21 never-smokers, who provided four first morning urine samples 2–5 days apart, and one additional sample roughly 1 month later. The second cohort (World Trade Center-Health Program (WTC-HP)) consisted of 78 individuals, including 52 never-smokers, 22 former smokers and 4 current smokers, who provided 2 spot urine samples 6 months apart, on average. Intra-class correlation was computed for groups of replicates from each individual to assess temporal variability. The median creatinine-adjusted U-Cd level (0.19 and 0.21 μg/g in the HOPE and WTC-HP, respectively) was similar to levels recorded in the United States by the National Health and Nutrition Examination Survey. The intra-class correlation (ICC) was high (0.76 and 0.78 for HOPE and WTC-HP, respectively) and similar between cohorts, irrespective of whether samples were collected days or months apart. Both single spot or first morning urine cadmium samples show good to excellent reproducibility in low-exposure populations.