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Aggregated Cumulative County Arsenic in Drinking Water and Associations with Bladder, Colorectal, and Kidney Cancers, Accounting for Population Served
Citation:
Krajewski, A., M. Jimenez, K. Rappazzo, D. Lobdell, AND J. Jagai. Aggregated Cumulative County Arsenic in Drinking Water and Associations with Bladder, Colorectal, and Kidney Cancers, Accounting for Population Served. Journal of Exposure Science and Environmental Epidemiology . Nature Publishing Group, London, Uk, 31(6):979-989, (2021). https://doi.org/10.1038/s41370-021-00314-8
Impact/Purpose:
This study addresses research questions under Sustainable and Healthy Communities (Project 2.62 Community Public Health & Well-Being). The Center for Public Health and Environmental Assessment in the Public Health and Environmental Systems Division, Epidemiology Branch is currently engaged in research aimed at assessing public health conditions related to environmental stressors. This research linked multiple environmental and health databases to assess the effects of arsenic concentrations in drinking water on bladder, colorectal and kidney cancers. This study also used a novel method to try to account for population served by the community water systems. The associations of arsenic in drinking water and bladder, colorectal, and kidney cancers were consistently stronger when proportioning the exposure based on population served, and thus, weighting by population served provided a better ecological measure of exposure.
Description:
Background. Many studies neglect to account for variation in population served by community water systems (CWSs) when aggregating CWS-level contaminant concentrations to county level. Objective. 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. Methods. 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). Results. 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. Significance Weighting by CWS population served accounts for some potential exposure assignment error in epidemiologic analysis.
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DOI: Aggregated Cumulative County Arsenic in Drinking Water and Associations with Bladder, Colorectal, and Kidney Cancers, Accounting for Population Served