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NIH Record - 75th Anniversary - National Institutes of Health

Study Links Long-Term Exposure to Air Pollution and Emphysema

Smoke billows from power plant smokestacks.

Long-term exposure to air pollution was linked to increases in emphysema between 2000 and 2018.

Photo: Kodda/Getty Images

Long-term exposure to air pollution was linked to increases in emphysema between 2000 and 2018, according to a new study funded by NIEHS and NHLBI. Emphysema, usually associated with cigarette smoking, is a chronic disease in which lung tissue is destroyed and unable to effectively transfer oxygen in the body. The study is published in the Journal of the American Medical Association.

“These findings may offer one explanation for why emphysema is found in some people who never smoked,” said Dr. James Kiley, director of NHLBI’s Division of Lung Diseases. “The study’s results, duration and timing offer insight into the long-term effects of air pollution on the U.S. population.”

The relationship between various air pollutants and emphysema was measured through computed tomography (CT) lung imaging and lung function testing. Consistent results were found in these varied metropolitan regions: Winston-Salem, N.C.; St. Paul, Minn.; New York City; Baltimore; Chicago; and Los Angeles. Participants came from the Multi-Ethnic Study of Atherosclerosis (MESA), a medical research study involving more than 7,000 men and women from the 6 localities.

“The combined health effect of multiple air pollutants—ozone, fine particles known as PM2.5, nitrogen oxides and black carbon—was greater than when the pollutants were assessed individually,” said Dr. Bonnie Joubert, a scientific program director at NIEHS. “With the study’s long-running duration, repeated CT scans allowed analysis of changes in emphysema over time.”

Researchers measured all major air pollutants with longitudinal increases in percentage of emphysema revealed by more than 15,000 CT scans acquired from 2000 to 2018. Over the same period, MESA carefully tracked air pollution. MESA is unique in its meticulous characterization of air pollution exposures along with repeated CT scans of lungs in study participants.

Emphysema is a debilitating disease. People with emphysema have difficulty breathing, along with a persistent cough and phlegm. It makes physical and social activities difficult, creates work hardships and may result in detrimental emotional conditions. Its development can be a slow, lifelong process. Emphysema is not curable, but treatments help manage the disease.

“We need to assess the effectiveness of strategies to control air pollutants in our efforts to improve heart and lung health,” said Dr. David Goff, director of NHLBI’s Division of Cardiovascular Sciences. “At the same time, people need to remember the importance of a healthy diet, physical activity and tobacco smoking cessation for overall health.”

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