Oak Ridge Institute for Science and Education (ORISE) Postdoctoral Fellow at United States Environmental Protection Agency (US EPA), Research Triangle Park, NC, USA.
US EPA, Office of Research and Development, Center for Public Health & Environmental Assessment, Research Triangle Park, NC, USA.
J Expo Sci Environ Epidemiol. 2021 Nov;31(6):979-989. doi: 10.1038/s41370-021-00314-8. Epub 2021 Mar 10.
Many studies neglect to account for variation in population served by community water systems (CWSs) when aggregating CWS-level contaminant concentrations to county level.
In an ecological epidemiologic analysis, we explored two methods-unweighted and weighted (proportion of CWS population served by county population)-to account for population served by CWS in association between arsenic and three cancers to determine the impact of population served on aggregated measures of exposure.
CWS arsenic concentration data for 19 states were obtained from Centers for Disease Control and Prevention (CDC) National Environmental Public Health Tracking Network for 2000-10, aggregated to county level, and linked to county-level cancer data for 2011-5 from National Cancer Institute and CDC State Cancer Profiles. Negative binomial regression models estimated adjusted risk ratios (aRR) and 95% confidence intervals (CI) between county-level bladder, colorectal, and kidney cancers and quartiles of aggregated cumulative county-level arsenic concentration (ppb-years).
We observed positive associations between the highest quartile of exposure, compared to the lowest, of aggregated cumulative county-level arsenic concentration (ppb-year) for bladder [weighted aRR: 1.89(1.53, 2.35)], colorectal [1.64(1.33, 2.01)], and kidney [1.69(1.37, 2.09)] cancers. We observed stronger associations utilizing the weighted exposure assessment method. However, inferences from this study are limited due to the ecologic nature of the analyses and different analytic study designs are needed to assess the utility that the weighted by CWS population served metric has for exposure assessment.
Weighting by CWS population served accounts for some potential exposure assignment error in epidemiologic analysis.
许多研究在将社区供水系统（CWS）的污染物浓度汇总到县一级时，忽略了考虑为这些系统供水的人群的变异性。
在生态流行病学分析中，我们探索了两种方法——非加权和加权（县人口中由 CWS 服务的人口比例）——以解释 CWS 所服务的人口与砷和三种癌症之间的关系，以确定所服务人口对汇总暴露指标的影响。
从疾病控制与预防中心（CDC）国家环境公共卫生跟踪网络获得了 19 个州的 CWS 砷浓度数据，这些数据在 2000 年至 2010 年期间进行了汇总，并按县一级进行了汇总，并与国家癌症研究所和疾病预防控制中心州癌症档案中 2011 年至 2015 年的县一级癌症数据进行了关联。负二项回归模型估计了县一级膀胱癌、结直肠癌和肾癌与汇总的累积县一级砷浓度（ppb-年）四分位数之间的调整风险比（aRR）和 95%置信区间（CI）。
我们观察到，与最低累积县一级砷浓度（ppb 年）四分位数相比，最高四分位数的暴露与膀胱癌[加权 aRR：1.89（1.53，2.35）]、结直肠癌[1.64（1.33，2.01）]和肾癌[1.69（1.37，2.09）]癌症之间存在正相关关系。我们观察到，使用加权暴露评估方法，关联更为强烈。然而，由于分析的生态性质，这项研究的推论受到限制，需要进行不同的分析研究设计来评估加权 CWS 所服务人口的指标在暴露评估中的实用性。
加权 CWS 所服务的人口可以在流行病学分析中减少一些潜在的暴露分配错误。
