County-level air quality and the prevalence of diagnosed chronic kidney disease in the US Medicare population

• Type of Material: Article
• Authors: Jennifer Bragg-Gresham, University of Michigan; Hal Morgenstern, University of Michigan; William McClellan, Emory University; Sharon Saydah, Centers for Disease Control and Prevention; Meda Pavkov, Centers for Disease Control and Prevention; Desmond Williams, Centers for Disease Control and Prevention; Neil Powe, University of California; Delphine Tuot, University of California; Raymond Hsu, University of California; Rajiv Saran, University of Michigan
• Language: English
• Date: 2018-07-31
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
• License: Creative Commons Creative Commons CC0 1.0 Universal
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0200612
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 13
• Issue: 7
• Start Page: e0200612
• End Page: e0200612
• Grant/Funding Information: This research was supported by the Supporting, Maintaining and Improving the Surveillance System for Chronic Kidney Disease in the U.S., Cooperative Agreement Number, U58 DP006254, funded by the Centers for Disease Control and Prevention.
• Keywords: RISK-FACTORS; POLLUTION; OUTCOMES; Multidisciplinary Sciences; HEALTH; OBESITY; Science & Technology - Other Topics; CARDIOVASCULAR-DISEASE; LONG-TERM EXPOSURE; RENAL-FUNCTION; FINE PARTICULATE MATTER; Science & Technology; UNITED-STATES
• Research Categories: Health Sciences, Public Health; Health Sciences, Epidemiology

Abstract

Background Considerable geographic variation exists in the prevalence of chronic kidney disease across the United States. While some of this variability can be explained by differences in patient-level risk factors, substantial variability still exists. We hypothesize this may be due to understudied environmental exposures such as air pollution. Methods Using data on 1.1 million persons from the 2010 5% Medicare sample and Environmental Protection Agency air-quality measures, we examined the association between county-level particulate matter 2.5 μm (PM2.5) and the prevalence of diagnosed CKD, based on claims. Modified Poisson regression was used to estimate associations (prevalence ratios [PR]) between county PM2.5concentration and individual-level diagnosis of CKD, adjusting for age, sex, race/ethnicity, hypertension, diabetes, and urban/rural status. Results Prevalence of diagnosed CKD ranged from 0% to 60% by county (median = 16%). As a continuous variable, PM2.5concentration shows adjusted PR of diagnosed CKD = 1.03 (95% CI: 1.02–1.05; p<0.001) for an increase of 4 μg/m3in PM2.5. Investigation by quartiles shows an elevated prevalence of diagnosed CKD for mean PM2.5levels 14 μg/m3(highest quartile: PR = 1.05, 95% CI: 1.03–1.07), which is consistent with current ambient air quality standard of 12 μg/m3, but much lower than the level typically considered healthy for sensitive groups (~40 μg/m3). Conclusion A positive association was observed between county-level PM2.5concentration and diagnosed CKD. The reliance on CKD diagnostic codes likely identified associations with the most severe CKD cases. These results can be strengthened by exploring laboratory-based diagnosis of CKD, individual measures of exposure to multiple pollutants, and more control of confounding.