Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada.
Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON, Canada; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, ON, Canada.
Int J Hyg Environ Health. 2021 May;234:113704. doi: 10.1016/j.ijheh.2021.113704. Epub 2021 Mar 6.
People are often concurrently exposed to numerous chemicals. Here we sought to leverage existing large biomonitoring datasets to improve our understanding of multi-chemical exposures in a population. Using nationally-representative data from the 2012-2015 Canadian Health Measures Survey (CHMS), we developed Exposure Load, a metric that counts the number of chemicals measured in people above a defined concentration threshold. We calculated Exposure Loads based on five concentration thresholds: the analytical limit of detection (LOD) and the 50th, 75th, 90th and 95th percentiles. Our analysis considered 44 analyte biomarkers representing 26 chemicals from the 2012-2015 CHMS; complete biomarker data were available for 1858 participants aged 12-79 years following multiple imputation of results that were missing due to sample loss. Chemicals may have one or more biomarkers, and for the purposes of Exposure Load calculation, participants were considered to be exposed to a chemical if at least one biomarker was above the threshold. Distributions of Exposure Loads are reported for the total population, as well as by age group, sex and smoking status. Canadians had an Exposure Load between 9 and 21 (out of 26) when considering LOD as the threshold, with the majority between 13 and 18. At higher thresholds, such as the 95th percentile, the majority of Canadians had an Exposure Load between 0 and 3, although some people had an Exposure Load of up to 15, indicating high exposures to multiple chemicals. Adolescents aged 12-19 years had significantly lower Exposure Loads than adults aged 40-79 years at all thresholds and adults aged 20-39 years at the 50th and 75th percentiles. Smokers had significantly higher Exposure Loads than nonsmokers at all thresholds except the LOD, which was expected given that tobacco smoke is a known source of certain chemicals included in our analysis. No differences in Exposure Loads were observed between males and females at any threshold. These findings broadly suggest that Canadians are concurrently exposed to many chemicals at lower concentrations and to fewer chemicals at high concentrations. They should assist in identifying vulnerable subpopulations disproportionately exposed to numerous chemicals at high concentrations. Future work will use Exposure Loads to identify prevalent chemical combinations and their link with adverse health outcomes in the Canadian population. The Exposure Load concept can be applied to other large datasets, through collaborative efforts in human biomonitoring networks, in order to further improve our understanding of multiple chemical exposures in different populations.
人们经常同时接触多种化学物质。在这里，我们利用现有的大型生物监测数据集来提高对人群中多化学物质暴露的理解。使用来自 2012-2015 年加拿大健康测量调查（CHMS）的全国代表性数据，我们开发了暴露负荷，这是一种衡量标准，用于计算超过定义浓度阈值的化学物质数量。我们基于五个浓度阈值计算了暴露负荷：分析检测限（LOD）和第 50、75、90 和 95 百分位数。我们的分析考虑了来自 2012-2015 年 CHMS 的代表 26 种化学物质的 44 种分析物生物标志物；通过对由于样本丢失而缺失的结果进行多次插补，为 1858 名年龄在 12-79 岁的参与者计算了暴露负荷。一种化学物质可能有一个或多个生物标志物，并且为了计算暴露负荷的目的，如果至少有一种生物标志物超过了阈值，则认为参与者接触到了该化学物质。报告了总人群以及按年龄组、性别和吸烟状况划分的暴露负荷分布。当将 LOD 作为阈值时，加拿大的暴露负荷在 9 到 21（26 种化学物质）之间，其中大多数在 13 到 18 之间。在较高的阈值下，例如 95 百分位数，大多数加拿大的暴露负荷在 0 到 3 之间，尽管有些人的暴露负荷高达 15，表明他们同时接触了多种高浓度化学物质。所有阈值下，12-19 岁的青少年的暴露负荷均显著低于 40-79 岁的成年人，20-39 岁的成年人在 50 百分位和 75 百分位下也是如此。除 LOD 外，吸烟者的暴露负荷均高于不吸烟者，这是因为烟草烟雾是我们分析中包含的某些化学物质的已知来源。在任何阈值下，男性和女性之间的暴露负荷均无差异。这些发现大致表明，加拿大同时接触许多浓度较低的化学物质，接触浓度较高的化学物质较少。它们有助于确定浓度较高的大量化学物质不成比例地暴露的脆弱亚人群。未来的工作将使用暴露负荷来确定普遍存在的化学物质组合及其与加拿大人群不良健康结果之间的联系。通过在人类生物监测网络中的合作努力，可以将暴露负荷概念应用于其他大型数据集，以进一步提高我们对不同人群中多种化学物质暴露的理解。
