Can air pollution damage your kidneys?

The detrimental effects of air pollution are not only evident in the respiratory and circulatory systems but also extend to renal function. The kidneys are particularly vulnerable to the toxic effects of environmental pollutants due to their critical role in filtration. Environmental and occupational exposure to pollutants remains a common cause of kidney disease globally, especially in developing countries. Up to 22% of the global disease burden and 23% of deaths are attributed to environmental pollution, meaning that the general population is inevitably exposed to harmful pollutants.

While comprehensive community data from India is lacking, studies from other regions have demonstrated that long-term exposure to particulate matter (PM) less than 2.5 μm in aerodynamic diameter (PM2.5) is linked to an increased risk of membranous nephropathy and a more rapid decline in renal function. Membranous nephropathy is a kidney disease caused by damage to the kidney’s filtration system, leading to significant protein leakage into the urine. It is believed that the damage is due to particulate matter exposure.

A recent study published in the Journal of the American Society of Nephrology highlighted the role of air pollution in the rising risk of new kidney disease cases and the accelerated progression of chronic kidney disease (CKD) to dialysis. The study tracked 2.5 million veterans, initially free of kidney disease when screened in 2003 and 2004, over an average period of 8.5 years. Researchers compared their health outcomes to air pollution levels, monitored by the Environmental Protection Agency (EPA) and NASA. To ensure accuracy, they accounted for recent improvements in air quality in the U.S. and patients' risk factors for kidney disease (e.g., age, race, sex, heart disease, diabetes, hypertension, smoking, obesity, and poverty). The study found that for every 10-microgram increase in pollution per cubic meter of air, there was a 25-37% increase in new kidney disease cases, a 36% rise in rapid kidney function decline, and a 31% increase in the risk of kidney failure requiring dialysis. The study estimated that air pollution was responsible for approximately 45,000 new CKD cases and 2,438 patients starting dialysis during the study period.

Similarly, studies in Taiwan and Korea have also identified links between elevated PM air pollution levels and reduced renal function, as well as an increased risk of developing CKD. In Europe, short-term exposure to elevated pollution levels was associated with a decrease in estimated glomerular filtration rate (eGFR), with PM and sulfur dioxide (SO2) being the primary pollutants affecting kidney function. Additionally, medium-term exposure to increased annual concentrations of PM2.5 and nitrogen dioxide (NO2) resulted in a higher number of CKD patients.

In India, the incidence of CKD is on the rise. Data from the Indian Society of Nephrology registry shows that a significant proportion (16%) of CKD cases have unknown causes. It is possible that air pollution is contributing to this unexplained rise in CKD.