Associations of ambient coarse particulate matter, nitrogen dioxide, and carbon monoxide with the risk of kidney disease: a cohort study

Background: Experimental evidence and preliminary clinical evidence suggest that environmental air pollution adversely effects kidney health. Previous work has examined the association between fine particulate matter and risk of kidney disease; however, the association between ambient coarse particulate matter (PM10; ≤10 μm in aerodynamic diameter), nitrogen dioxide (NO2), and carbon monoxide (CO) and risk of incident chronic kidney disease, chronic kidney disease progression, and end-stage renal disease is not clear. Methods: We merged multiple large databases, including those of the Environmental Protection Agency and the Department of Veterans Affairs, to build a cohort of US veterans, and used survival models to evaluate the association between PM10, NO2, and CO concentrations and risk of incident estimated glomerular filtration rate (eGFR) of less than 60 mL/min per 1·73 m2, incident chronic kidney disease, eGFR decline of 30% or more, and end-stage renal disease. We treated exposure as time-varying when it was updated annually and as cohort participants moved. Findings: Between Oct 1, 2003, and Sept 30, 2012, 2 010 398 cohort participants were followed up over a median of 8·52 years (IQR 8·05–8·80). An increased risk of eGFR of less than 60 mL/min per 1·73 m2 was associated with an IQR increase in concentrations of PM10 (hazard ratio 1·07, 95% CI 1·06–1·08), NO2 (1·09, 1·08–1·10), and CO (1·09, 1·08–1·10). An increased risk of incident chronic kidney disease was associated with an IQR increase in concentrations of PM10 (1·07, 1·05–1·08), NO2 (1·09, 1·08–1·11), and CO (1·10, 1·08–1·11). An increased risk of an eGFR decline of 30% or more was associated with an IQR increase in concentrations of PM10 (1·08, 1·07–1·09), NO2 (1·12, 1·10–1·13), and CO (1·09, 1·08–1·10). An increased risk of end-stage renal disease was associated with an IQR increase in concentrations of PM10 (1·09, 1·06–1·12), NO2 (1·09, 1·06–1·12), and CO (1·05, 1·02–1·08). Spline analyses suggested a monotonic increasing association between PM10, NO2, and CO concentrations and risk of kidney outcomes. Interpretation: Environmental exposure to higher concentrations of PM10, NO2, and CO is associated with increased risk of incident chronic kidney disease, eGFR decline, and end-stage renal disease. Funding: US Department of Veterans Affairs.