County-level associations between drinking water PFAS contamination and COVID-19 mortality in the United States
By Jahred M. Liddie, Marie-Abèle Bind, Mahesh Karra, and Elsie M. Sunderland
Nature
October 6, 2024
DOI: 10.1038/s41370-024-00723-5
Background
Epidemiologic and animal studies both support relationships between exposures to per- and polyfluoroalkyl substances (PFAS) and harmful effects on the immune system. Accordingly, PFAS have been identified as potential environmental risk factors for adverse COVID-19 outcomes.
Objective
Here, we examine associations between PFAS contamination of U.S. community water systems (CWS) and county-level COVID-19 mortality records. Our analyses leverage two datasets: one at the subnational scale (5371 CWS serving 621 counties) and one at the national scale (4798 CWS serving 1677 counties). The subnational monitoring dataset was obtained from statewide drinking monitoring of PFAS (2016–2020) and the national monitoring dataset was obtained from a survey of unregulated contaminants (2013–2015).
Methods
We conducted parallel analyses using multilevel quasi-Poisson regressions to estimate cumulative incidence ratios for the association between county-level measures of PFAS drinking water contamination and COVID-19 mortality prior to vaccination onset (Jan-Dec 2020). In the primary analyses, these regressions were adjusted for several county-level sociodemographic factors, days after the first reported case in the county, and total hospital beds.
Results
In the subnational analysis, detection of at least one PFAS over 5 ng/L was associated with 12% higher [95% CI: 4%, 19%] COVID-19 mortality. In the national analysis, detection of at least one PFAS above the reporting limits (20–90 ng/L) was associated with 13% higher [95% CI: 8%, 19%] COVID-19 mortality.
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