LaKind Associates, LLC, Catonsville, MD, USA; Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA.
Canadian Health Measures Survey, Centre for Population Health Statistics, Statistics Canada, Ottawa, Ontario, Canada.
Environ Res. 2019 Jun;173:318-329. doi: 10.1016/j.envres.2019.03.047. Epub 2019 Mar 26.
The use of biomonitoring data as an indicator of national levels of human exposure to environmental chemicals has grown in importance and prevalence. Nationally representative urinary bisphenol A (BPA) data are now available for Canada, the United States and Korea. Here we address the following questions: Are urinary BPA data from these countries comparable? What can be discerned regarding geographic and/or temporal similarities or differences? Are there generalizable lessons to be learned regarding comparison of biomonitoring results from different countries?
We examined underlying methods and resultant urinary BPA data from national surveys of three countries: Canada (Canadian Health Measures Survey, CHMS, 2009-2015); United States (National Health and Nutrition Examination Survey, NHANES, 2009-2014); and Korea (Korean National Environmental Health Survey, KoNEHS, 2009-2014). We estimated BPA daily intakes on both a volume- and creatinine-adjusted basis.
The three countries use similar methods for analyzing urine samples for BPA and participate in external proficiency testing with acceptable results. Field blanks are only used in the CHMS program. There were program-specific differences in fasting times of participants. Median urinary BPA levels in Canada remained relatively constant over the three cycles (1.1-1.2 ng/ml), while US levels decreased (from 1.9 to 1.3 ng/ml) and Korean levels increased (from 0.7 to 1.1 ng/ml) over similar time periods. The most recent survey year data indicate that levels do not differ substantially across countries. Canadian urinary BPA levels have been stable; the subtle, non-significant decrease in intakes may be due to higher body weight in the more recent Canadian surveys. In contrast, the decrease in intakes in the US appears to be due to decreases in urinary BPA as body weights in the US have been stable. Estimated 95th percentile intakes are over an order of magnitude below current health-based guidance values.
Our assessment of urinary BPA data from Canada, the US and Korea indicates that methodological differences, methods for dilution adjustment, and population characteristics should be carefully considered when interpreting biomonitoring data. Despite the plethora of publications describing issues with use of creatinine levels for urinary dilution adjustment, there have been no major methodological advances that would assist in interpreting urinary chemical data. A combination of biomonitoring and traditional exposure assessment approaches may be needed to fully assess human exposures to BPA and other chemicals.
National biomonitoring surveys provide important information on population levels of chemicals such as BPA and can assist in understanding temporal and geographic similarities, differences, and trends. However, caution must be exercised when using these data to draw anything but broad conclusions, due to both intercountry methodological differences and factors affecting urinary chemical levels that are still poorly understood. While the issues raised in this paper do not appear to be a major concern specifically for the national-scale monitoring of BPA described here, they must be considered when comparing data for other chemicals measured as part of both national and smaller-scale biomonitoring-based research as well as for BPA data from other studies.
将生物监测数据用作评估人群环境化学物质暴露水平的指标，其重要性和普遍性日益增加。目前，加拿大、美国和韩国均已具备全国代表性的尿液双酚 A（BPA）数据。在此，我们将探讨以下问题：这些国家的尿液 BPA 数据是否具有可比性？在地理和/或时间方面，是否存在相似或不同之处？对于比较来自不同国家的生物监测结果，能否得出普遍适用的经验教训？
我们研究了三个国家的全国性调查所采用的基本方法和相应的尿液 BPA 数据：加拿大（加拿大健康测量调查，CHMS，2009-2015 年）；美国（国家健康和营养检查调查，NHANES，2009-2014 年）；以及韩国（韩国国家环境健康调查，KoNEHS，2009-2014 年）。我们基于体积和肌酐调整，分别估算了 BPA 的日摄入量。
这三个国家均采用类似的方法来分析尿液样本中的 BPA，并参与了外部能力验证测试，结果符合要求。CHMS 方案中仅使用现场空白。各方案的参与者空腹时间存在差异。加拿大在三个周期内的尿液 BPA 中位水平保持相对稳定（1.1-1.2ng/ml），而美国的水平呈下降趋势（从 1.9ng/ml 降至 1.3ng/ml），韩国的水平呈上升趋势（从 0.7ng/ml 增至 1.1ng/ml）。最近调查年份的数据表明，各国之间的水平差异不显著。加拿大的尿液 BPA 水平较为稳定；摄入量的轻微、非显著下降可能归因于最近调查中加拿大人体重增加。相比之下，美国摄入量的下降似乎是由于尿液 BPA 下降所致，而美国的体重保持稳定。估计的 95 百分位数摄入量比当前基于健康的指导值低一个数量级以上。
我们对加拿大、美国和韩国的尿液 BPA 数据进行了评估，结果表明，在解释生物监测数据时，应仔细考虑方法学差异、稀释调整方法以及人群特征。尽管有大量文献描述了肌酐水平用于尿液稀释调整的问题，但在解释尿液化学数据方面尚未取得重大方法学进展。可能需要结合生物监测和传统暴露评估方法，以全面评估 BPA 和其他化学物质对人体的暴露情况。
国家生物监测调查提供了有关 BPA 等化学物质在人群水平的重要信息，并有助于了解时间和地理上的相似性、差异和趋势。但是，在利用这些数据得出结论时，必须谨慎，因为国家间存在方法学差异，且影响尿液化学物质水平的因素仍未得到充分理解。虽然本文提出的问题似乎不是本文所描述的全国范围内监测 BPA 时的一个主要问题，但在比较作为国家和较小规模基于生物监测的研究的一部分以及其他研究中 BPA 数据的其他化学物质测量数据时，必须考虑这些问题。
