Air pollution accelerates progression of emphysema of lungs: Study

Air pollution especially ozone air pollution which is increasing with climate change accelerates the progression of emphysema of the lung, suggests a new study.

The research published in the journal 'JAMA' demonstrated an association between long-term exposures to all major air pollutants -- especially ozone -- with an increase in emphysema seen on lung scans.

Emphysema is a condition in which destruction of lung tissue leads to wheezing, coughing and shortness of breath, and increases the risk of death.

"We were surprised to see how strong air pollution's impact was on the progression of emphysema on lung scans, in the same league as the effects of cigarette smoking, which is by far the best-known cause of emphysema," said Dr Joel Kaufman, the study's senior co-author.

"Rates of chronic lung diseases are going up and increasingly it is recognised that this disease occurs in non-smokers. We really need to understand what's causing chronic lung disease, and it appears that air pollution exposures that are common and hard to avoid might be a major contributor," said Kaufman.

The results are based on an extensive, 18-year study involving more than 7,000 people and a detailed examination of the air pollution they encountered between 2000 and 2018 in six metropolitan regions across the US: Chicago, Winston-Salem, N.C., Baltimore, Los Angeles, St. Paul, Minnesota, and New York. The participants were drawn from the Multi-Ethnic Study of Atherosclerosis (MESA) Air and Lung studies.

"To our knowledge, this is the first longitudinal study to assess the association between long-term exposure to air pollutants and progression of per cent emphysema in a large, community-based, multi-ethnic cohort," said Meng Wang, study's first author.

The authors developed novel and accurate exposure assessment methods for air pollution levels at the homes of study participants, collecting detailed measurement of exposures over years in these metropolitan regions, and measurements at the homes of many of the participants.

"As temperatures rise with climate change ground-level ozone will continue to increase unless steps are taken to reduce this pollutant. But it's not clear what level of the air pollutants, if any, is safe for human health," said Dr R Graham Barr, senior author of the study.

Emphysema was measured from CT scans that identify holes in the small air sacs of the participants' lungs, and lung function tests, which measure the speed and amount of air breathed in and out.

"This study adds to growing evidence of a link between air pollution and emphysema. A better understanding of the impact of pollutants on the lung could lead to more effective ways of preventing and treating this devastating disease," said James Kiley, director of the Division of Lung Diseases at the National Heart, Lung, and Blood Institute, part of the National Institutes of Health.

"It's important that we continue to explore factors that impact emphysema particularly in a large, well-characterised multi-ethnic group of adults such as those represented by MESA," Kiley added.