Air Pollution Linked to Increased Risk of Kidney Disease

The likelihood of developing membranous nephropathy (MN), an immune disorder of the kidneys that can lead to kidney failure, may be increased with exposure to air pollution, according to a new study.

In order to examine the effect of air pollution exposure on kidney health, researchers examined data from 71,151 biopsies from 938 hospitals spanning 282 cities in China from 2004 to 2014. After age and region standardization, they identified immunoglobulin A (IgA) nephropathy as the leading type of kidney disease, with a frequency of 28.1%, followed by MN, with a frequency of 23.4%. The adjusted odds for MN increased 13% annually over the 11-year study period, whereas the proportions of other major kidney diseases remained stable.
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During the study period, 3-year average fine-particle exposure varied among the 282 cities, ranging from 6 to 114 μg/m³ (mean, 52.6 μg/m³). Each 10 μg/m³ increase in fine-particle concentration was associated with 14% higher odds for MN (odds ratio, 1.14; 95% confidence interval [CI], 1.10-1.18). The researchers also found a higher 3-year average air-quality index to be associated with increased risk of MN.

“In addition to respiratory and cardiovascular disease, long-term exposure to small particulate matter might be involved in the induction of organ-specific auto-immunity and injury in distal organs, such as kidney,” said study author Fan Fan Hou, MD, PhD, director of the Division of Nephrology at Nanfang Hospital in Guangzhou, China. “The effect of air pollution on the risk of MN was quite large. About one-sixth of MN in China was related to air pollution.”

“Air pollution should be recognized as a major risk factor of MN. Patients at high risk of MN should avoid long-term exposure to air pollution,” Dr Hou said. “This study may trigger new avenues of research into the mechanisms of pollution-related diseases. In future studies, we plan to investigate the roles of different types of pollution in MN and the possible mechanisms underlying air-pollution–induced kidney damage.”

—Mike Bederka

Reference:

Xu X, Wang G, Chen N, et al. Long-term exposure to air pollution and increased risk of membranous nephropathy in China [published online June 30, 2016]. J Am Soc Nephrol. doi:10.1681/ASN.2016010093.