Human Exposure and Atmospheric Sciences Division, NERL/ORD, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
J Toxicol Environ Health A. 2013;76(12):747-66. doi: 10.1080/15287394.2013.821394.
Human biomarker measurements in tissues including blood, breath, and urine can serve as efficient surrogates for environmental monitoring because a single biological sample integrates personal exposure across all environmental media and uptake pathways. However, biomarkers represent a "snapshot" in time, and risk assessment is generally based on long-term averages. In this study, a statistical approach is proposed for estimating long-term average exposures from distributions of spot biomarker measurements using intraclass correlations based upon measurement variance components from the literature. This methodology was developed and demonstrated using a log-normally distributed data set of urinary OH-pyrene taken from our own studies. The calculations are generalized for any biomarker data set of spot measures such as those from the National Health and Nutrition Evaluation Studies (NHANES) requiring only spreadsheet calculations. A three-tiered approach depending on the availability of metadata was developed for converting any collection of spot biomarkers into an estimated distribution of individual means that can then be compared to a biologically relevant risk level. Examples from a Microsoft Excel-based spreadsheet for calculating estimates of the proportion of the population exceeding a given biomonitoring equivalent level are provided as an appendix.
人体组织（包括血液、呼吸和尿液）中的生物标志物测量可以作为环境监测的有效替代物，因为单个生物样本综合了个人在所有环境介质和吸收途径中的暴露情况。然而，生物标志物仅代表一个“快照”，风险评估通常基于长期平均值。在这项研究中，提出了一种使用基于文献中测量方差分量的组内相关来从点生物标志物测量分布估计长期平均暴露的统计方法。该方法是使用我们自己的研究中从尿液中提取的 OH-苊的对数正态分布数据集开发和验证的。该计算方法适用于任何点测量的生物标志物数据集，例如来自国家健康和营养评估研究（NHANES）的数据集，只需要电子表格计算。根据元数据的可用性，开发了一种三层方法，用于将任何点生物标志物集合转换为个体平均值的估计分布，然后可以将其与生物相关的风险水平进行比较。作为附录，提供了一个基于 Microsoft Excel 的电子表格，用于计算超过给定生物监测等效水平的人口比例的估计值。
