Elderly asthma patients living near busy highways and heavy industry in Southeast Michigan believed that air pollution was making their breathing more difficult.
A recent study by Michigan State University researchers concluded they were right.
As levels of tiny airborne particles known as PM2.5 rose in the air, the study participants increased their use of asthma control drugs containing corticosteroids, which can have adverse health effects, including osteoporosis and impaired immune function.
The participants’ self-reported shortness of breath was confirmed by lung-function tests.
“The higher their exposure to PM2.5, the worse their asthma symptoms were,” said Bengt Arnetz, the study’s lead author and chair of the College of Human Medicine’s Department of Family Medicine. “I think the most significant finding is that air pollution not only influenced how well they could breathe, but also how much asthma control drugs they used.”
The study, published in the Journal of Asthma, followed 28 men and 48 women — all 55 years old or older and diagnosed with asthma.
All 76 participants lived in an economically disadvantaged area of Dearborn. The researchers collected and analyzed air samples over time in the neighborhood and visited each participant’s home, looking for peeling paint, crumbling plaster, mold and mildew.
The participants answered multiple questions, including their perception of air pollution in the area, whether they suffered shortness of breath in recent months, how often they used rescue inhalers and corticosteroids, and the number of times they visited hospital emergency rooms due to asthma.
Each also rated his or her own respiratory health on a scale of one to five, with one being poor and five being excellent.
Their self-ratings of shortness of breath and use of asthma control drugs correlated with the air pollution level in the neighborhood, including the amount of PM2.5, the study found.
PM2.5 primarily comes from vehicle exhaust and the burning of wood, coal, petroleum and other fuels. Inhaling the tiny particles not only aggravates asthma symptoms, but can cause inflammation in the body, which can lead to heart attacks, strokes, high blood pressure, lung cancer and other serious health threats.
“Asthma is just obvious,” Arnetz said. “Among older people who are already health compromised, this adds onto that and increases the risk of early death.”
Yet the levels of PM2.5 did not exceed federal clean air standards, he said, saying that more needs to be done to reduce air pollution.
“We need to approach this from a systems perspective,” he said, finding ways to reduce PM2.5 levels and alerting the public, including asthmatics, when air pollution becomes a health hazard.
“This is a very costly disease,” Arnetz said.
The U.S. Centers for Disease Control and Prevention estimated that asthma costs the U.S. economy more than $80 billion a year in medical expenses, lost work days and deaths.
“If we could clean up the air, we could reduce a lot of healthcare costs,” Arnetz said.