United States Environmental Protection Agency, National Center for Environmental Assessment, Office of Research and Development, Washington, District of Columbia 20460, USA.
J Expo Sci Environ Epidemiol. 2012 Nov;22(6):632-40. doi: 10.1038/jes.2012.52. Epub 2012 Jun 6.
Human exposure to phthalates and bisphenol A (BPA) can be assessed through urinary biomonitoring, but methods to infer daily intakes assume that spot sample concentrations are comparable to daily average concentrations. We evaluate this assumption using human biomonitoring data from Germany and the United States (US). The German data comprised three regional studies with spot samples and one with full-day samples analyzed for phthalate metabolites. The US data included: a study on DEHP metabolites and BPA involving eight persons supplying all urine voids (from which 24-h samples were constructed) for seven consecutive days; NHANES spot sample data on DEHP metabolites and BPA; and a regional study of children with 48-h samples analyzed for BPA. In the German data, measures of central tendency differed, but spot and 24-h samples showed generally comparable variance including 95th percentiles and maxima equidistant from central tendency measures. In contrast, the US adult data from the eight-person study showed similar central tendencies for phthalate metabolites and BPA, but generally greater variability for the spot samples, including higher 95th percentiles and maxima. When comparing children's BPA concentrations in NHANES spot and 48-h samples, distributions showed similar central tendency and variability. Overall, spot urinary concentrations of DEHP metabolites and BPA have variability roughly comparable with corresponding 24-h average concentrations obtained from a comparable population, suggesting that spot samples can be used to characterize population distributions of intakes. However, the analysis also suggests that caution should be exercised when interpreting the high end of spot sample data sets.
人体接触邻苯二甲酸酯和双酚 A（BPA）可以通过尿液生物监测来评估，但推断日摄入量的方法假设点样浓度与日平均浓度相当。我们使用来自德国和美国的人体生物监测数据来评估这一假设。德国的数据包括三个区域性研究，其中有三个是采用点样进行的，一个是采用全日内样本分析邻苯二甲酸代谢物。美国的数据包括：一项涉及 DEHP 代谢物和 BPA 的研究，有 8 人连续 7 天提供所有尿液（从中构建 24 小时样本）；NHANES 关于 DEHP 代谢物和 BPA 的点样数据；以及一项针对儿童的区域性研究，对 BPA 进行 48 小时样本分析。在德国的数据中，集中趋势的测量结果有所不同，但点样和 24 小时样本的方差通常具有可比性，包括 95%分位数和最大值与集中趋势测量值等距。相比之下，来自 8 人研究的美国成年人数据显示，邻苯二甲酸代谢物和 BPA 的集中趋势相似，但点样样本的变异性通常更大，包括更高的 95%分位数和最大值。当比较 NHANES 点样和 48 小时样本中儿童的 BPA 浓度时，分布显示出相似的集中趋势和变异性。总体而言，DEHP 代谢物和 BPA 的点样尿液浓度的变异性与从可比人群中获得的相应 24 小时平均浓度大致相当，这表明点样样本可用于描述摄入量的人群分布。然而，该分析还表明，在解释点样样本数据集的高端值时应谨慎行事。
