Elevated levels of fine particulate matter <2.5 µm in aerodynamic diameter (PM2.5)
are associated with increased risk of cardiovascular outcomes and death, but their
association with risk of CKD and ESRD is unknown. We linked the Environmental Protection
Agency and the Department of Veterans Affairs databases to build an observational
cohort of 2,482,737 United States veterans, and used survival models to evaluate the
association of PM2.5 concentrations and risk of incident eGFR <60 ml/min per 1.73
m2, incident CKD, eGFR decline ≥30%, and ESRD over a median follow-up of 8.52 years.
County-level exposure was defined at baseline as the annual average PM2.5 concentrations
in 2004, and separately as time-varying where it was updated annually and as cohort
participants moved. In analyses of baseline exposure (median, 11.8 [interquartile
range, 10.1-13.7] µg/m3), a 10-µg/m3 increase in PM2.5 concentration was associated
with increased risk of eGFR<60 ml/min per 1.73 m2 (hazard ratio [HR], 1.21; 95% confidence
interval [95% CI], 1.14 to 1.29), CKD (HR, 1.27; 95% CI, 1.17 to 1.38), eGFR decline
≥30% (HR, 1.28; 95% CI, 1.18 to 1.39), and ESRD (HR, 1.26; 95% CI, 1.17 to 1.35).
In time-varying analyses, a 10-µg/m3 increase in PM2.5 concentration was associated
with similarly increased risk of eGFR<60 ml/min per 1.73 m2, CKD, eGFR decline ≥30%,
and ESRD. Spline analyses showed a linear relationship between PM2.5 concentrations
and risk of kidney outcomes. Exposure estimates derived from National Aeronautics
and Space Administration satellite data yielded consistent results. Our findings demonstrate
a significant association between exposure to PM2.5 and risk of incident CKD, eGFR
decline, and ESRD.