Long-Term Exposure To PM2.5 And Repeated Measures Of Renal Function In Elderly Men: The VA Normative Aging Study

Abstract

Introduction: It is unknown if ambient fine particulate matter (PM2.5) is associated with lower renal function, a cardiovascular risk factor. We investigated if long-term PM2.5 exposure was associated with estimated glomerular filtration rate (eGFR) in a cohort of older men living in the Boston Metropolitan area. Methods: This longitudinal analysis included 681 participants from the Veterans Administration Normative Aging Study with up to four visits between 2000 and 2011 (n=1,749). Serum creatinine was measured at each visit and eGFR was calculated according to the Chronic Kidney Disease Epidemiology Collaboration equation. One-year exposure to PM2.5 prior to each visit was assessed using a validated spatiotemporal model. This model used satellite remote sensing aerosol optical depth data (at a resolution of 1x1km) as well as land use and weather parameters. eGFR was modeled in a time-varying linear mixed-effects regression model as a continuous function of 1-year PM2.5 adjusting for time since baseline visit, age at baseline visit, race, education, percentage below poverty in census tract, body mass index, anti-hypertensive medication use, diabetes, coronary heart disease, HDL cholesterol, smoking, alcohol intake, and season. Results: 1-year PM2.5 exposure was associated with lower eGFR level; an interquartile range increase in 1-year PM2.5 (2 μg/m3) was associated with a 2.16 mL/min/1.73 m2 lower eGFR (95%CI: -3.27, -1.06). 1-year PM2.5 exposure was also associated with the rate of decline in eGFR over time; a 2 μg/m3 increase in 1-year PM2.5 was associated with an additional annual change in eGFR of -0.61 mL/min/1.73 m2/yr (95%CI: -0.80, -0.41). The associations remained consistent after excluding individuals present with impaired renal function at the baseline visit, and adjusting for distance to nearest major roadway. Conclusion: The findings support the hypothesis that long-term PM2.5 exposure negatively affects renal function and renal function decline.