Exposure to high levels of air pollution containing fine particulate matter may increase an individual’s risks for albuminuria and chronic kidney disease (CKD), new study findings suggest.

A growing body of evidence has linked particulate matter less than 2.5 µm in diameter (PM2.5) with a variety of health problems, such as cardiovascular and respiratory diseases, diabetes mellitus, and early death. Recent studies have also linked PM2.5 with CKD death and increased hospitalization of hemodialysis patients.

In the current study, published in the Clinical Journal of the American Society of Nephrology, Matthew F. Blum, MD, of Johns Hopkins University School of Medicine in Baltimore, Maryland, and colleagues estimated monthly mean PM2.5 concentrations (µ/m3) for 10,997 participants in the Atherosclerosis Risk in Communities (ARIC) cohort who resided in 4 US localities: Forsyth County, North Carolina; Jackson, Mississippi; suburbs of Minneapolis, Minnesota; and Washington County, Maryland. ARIC participants (mean age 63 years) were initially free of CKD (mean estimated glomerular filtration rate [eGFR] 86 mL/min/1.73 m2) and were followed from 1996–1998 through 2016.

Each 1-µ/m3 increment in mean annual PM2.5 concentration was significantly associated with a 6.6% increase in urinary albumin to creatinine ratio (UACR) and a 5% increase in the risk for stage 3 or higher CKD (or 17.8 excess events per 1000 person-years), Dr Blum’s team reported. The investigators found no relationship between PM2.5 and baseline eGFR or conditions (such as cellulitis) serving as controls.

The current findings generally agree with some previous studies on the topic conducted in various countries.

“It is estimated that 17%–20% of the global toll of CKD burden may be attributable to PM2.5 pollution, and that the burden is unevenly distributed geographically and is more heavily tilted toward low and low-middle income countries, which might be least equipped to deal with the adverse health consequences of air pollution,” Ziyad Al-Aly, MD, and Benjamin Bowe, MPH, of Veterans Affairs St. Louis Health Care System, stated in an accompanying editorial.

 PM2.5 are small enough to reach distal airways and alveoli. The timing, duration, and specific components of exposure are likely important.

“The classic view that air pollution is a risk factor for upper and lower respiratory airways is now challenged by evidence that air pollution may also impact other organs such as heart, vessels, and kidneys,” Baris Afsar, MD, of Konya Numune State Hospital and colleagues stated in a 2018 review on air pollution and kidney disease published in Clinical Kidney Journal. “The inflammatory mediators induced by PM and other pollutants in the lungs could spill over into the circulation, resulting in systemic inflammation, oxidative stress and damage to distant organs including kidneys. However, there is also evidence of direct harm to the kidneys. The pathogenesis is still not fully understood.”

Fine particulate matter arises from many sources, including fossil fuel combustion, industrial processes, and natural sources such as wildfires or volcanic eruptions. Indoor sources of fine particles include smoke and fumes from tobacco, cooking, lit candles or oil lamps, fireplaces, and fuel-burning space heaters.

According to Dr Blum’s team, “These findings support the role of PM2.5 exposure as a potential risk factor for CKD and suggest PM2.5 mitigation efforts as a potential avenue for reducing CKD burden.”

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References

Blum MF, Surapaneni A, Stewart JD, et al. Particulate matter and albuminuria, glomerular filtration rate, and incident CKD. Clin J Am Soc Nephrol. doi: 10.2215/CJN.08350719

Al-Aly Z, Bowe B. Air pollution and kidney disease. Clin J Am Soc Nephrol. doi: 10.2215/CJN.16031219

Afsar B, Elsurer Afsar R, Kanbay A, Covic A, Ortiz A, Kanbay M. Air pollution and kidney disease: Review of current evidence. Clin Kid J. 12(1):19–32. doi: 10.1093/ckj/sfy111

Fine Particles (PM2.5) Questions and Answers. New York State Dept of Health. Accessed at https://www.health.ny.gov/environmental/indoors/air/pmq_a.htm

Fine particle air pollution linked with poor kidney health [news release]. American Society of Nephrology; February 27, 2020.

Wyatt L, Xi Y, Kshirsagar AV, Wade TJ, Rappold AG. Elevated PM2.5 increases daily hospital admission and readmission risk in chronic hemodialysis patients. Presented at the American Society of Nephrology’s Kidney Week 2019 meeting held November 5 to 10, 2019 in Washington DC. Abstract FR-PO432.

Bowe B, Xie Y, Yan Y, Al-Aly Z. Burden of cause-specific mortality associated with PM2.5 air pollution in the United States. JAMA Netw Open. 2019;2(11):e1915834. doi: 10.1001/jamanetworkopen.2019.15834