Breathing polluted air can lead to an increased risk of heart disease, stroke, lung disease and cancer, but as if that weren't enough, people in places like Los Angeles need to worry about an increased risk of kidney disease as well, according to new research published last week.
Researchers at St. Louis' Washington University School of Medicine tracked pollution levels in cities across the U.S., along with rates of kidney disease among nearly 2.5 million military veterans from 2004 to 2012, using data from the Environmental Protection Agency, NASA and the Department of Veterans Affairs. What they found was that as pollution levels rose, so did the rate of kidney disease among their subjects.
"There are about 45,000 new cases of kidney disease per year that can be attributed to air pollution," said Ziyad Al-Aly, senior author of the study, which was published in the Journal of the American Society of Nephrology.
The culprit is particulate matter that ends up in the air largely as a result of the burning of fossil fuels and organic matter. It's only 2.5 microns thick (a human hair is 50-70), which means that when it's inhaled it can easily enter the bloodstream through the lungs and spread throughout the body.
"We think that the kidney is especially prone to developing ... adverse consequences from bad air because it filters a huge amount of blood," said Al-Aly.
Researchers believe that the kidneys, which filter nearly 50 gallons of blood per day, are inundated with particulates. They can cause inflammation, oxidative stress and damage to the kidney tissue's DNA. Over time, kidney function can decrease, necessitating transplant or dialysis.
Southern Californians experience some of the highest levels of particulate matter in the U.S., according to the American Lung Association. Los Angeles has the fourth highest annual level, primarily because of the huge number of cars in the area.
The amount of particulate matter in L.A.'s air in 2016 was nearly double what the EPA considers safe. However, the Washington University researchers also found an increase in kidney disease in areas with particulate levels below the EPA's "safe" threshold.