Exposure to particulate matter (PM)—microscopic solid and liquid molecules suspended in the air—has been linked to the development and aggravation of both lung and cardiovascular diseases. Less is known about the effects of PM on chronic kidney disease and kidney failure. 

In a recent study, researchers from the Clinical Epidemiology Center in St. Louis, Missouri, investigated how fine PM, or particles of less than 2.5 microns, or 1/1000 of a millimeter, may affect the risk of chronic kidney disease (CKD) and end-stage kidney disease (ESKD).*

What they did

The scientists combined databases from the Environmental Protection Agency (EPA) and the Department of Veterans Affairs (VA) healthcare system to create a study cohort of 2,482,737 U.S veterans. They analyzed geographic PM2.5 air contamination data in relation to kidney function decline and new cases of ESKD over a median follow-up period of 8.52 years. 

The pieces of data that they looked at specifically were:

• incidence (new cases) of CKD (eGFR <60),
• eGFR decline ≥30%, and
• incidence of ESKD.

What they found

Of the study’s participants, made up largely of white males, the researchers found that participants living in areas of high PM2.5 concentrations were most likely to be:

• of black racial group;
• more likely to have hypertension, diabetes mellitus, cardiovascular disease, and a higher eGFR; and 
• more likely to be a current or former cigarette smoker.

They also found that areas with the highest levels of PM2.5 concentrations had a significantly higher population density.

Overall, their findings linked increased exposure to PM2.5 with a:

• higher risk of kidney disease,
• reduced GFR value (below 60), and
• increased risk of ESKD.

What this means

What the researchers found supports their “hypothesis that environmental exposure to elevated levels of PM2.5 is associated with increased risk of kidney disease” and “provides biologic plausibility,” as written in the study’s abstract. 

Their findings, which identify “air pollution as a potential contributor to kidney disease,” will:

• will assist in estimating the national and global burden of CKD;
• aid in policy discussions on how to decrease air pollution and its negative effects on both general health and specific diseases; and
• help the general public understand how hazardous air pollution can be.

Further studies are needed to understand the mechanisms by which small particulate air-borne pollutants affect the progression of CKD, as well as how they affect diverse populations.

*Bowe, B., Xie, Y., Li, T., Yan Y, et al. (2018). “Particulate Matter Air Pollution and the Risk of Incident CKD and Progression to ESRD.” Journal of the American Society of Nephrology.