Long-Term Exposure to Air Pollutants Increases Risk of Emphysema

The increase in emphysema incidences in the United States between 2000 and 2018 was connected to long-term exposure of ambient air pollutants, according to the authors of a new study.

Not only were the pollutants associated with emphysema progression, but they also were significantly associated with declined lung function.

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The study comprised 5780 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) study, which was conducted in 6 US metropolitan regions. 

The participants were followed for a median of 10 years. The researchers measured percent emphysema (defined as the percent of lung pixels less than -950 Hounsfield units) through cardiac computed tomography (CT) scan from 2000 to 2007 and through equivalent regions on lung CT scans from 2010 to 2018. These assessments were conducted up to 5 times on each participant. From 2004 to 2018, each participant underwent spirometry up to 3 times.

At baseline, median percent emphysema was 3%; this increased a mean of 0.58 percentage points per 10 years.

The researchers compared the data gathered from the tests with the residence-specific air pollutant concentrations of ambient ozone (O₃), fine particulate matter (PM_2.5), oxides of nitrogen (NO_x), and black carbon exposure from 1999 through the end of follow-up.

By doing this, the researchers determined there was a statistically significant association between baseline ambient concentrations of O₃, PM_2.5, NO_x, and black carbon with greater increases in emphysema incidence.

During follow-up, concentrations of O₃ and NO_x were associated with increases in emphysema incidence. Meanwhile, concentrations of PM_2.5 were not associated with emphysema increases. 

Baseline ambient O₃ was significantly associated with a faster decline in forced expiratory volume in the first second (FEV₁) per 10 years. No other pollutant had this association.

—Colleen Murphy

Reference:

Wang M, Pistenmaa Aaron C, Madrigano J, et al. Association between long-term exposure to ambient air pollution and change in quantitatively assessed emphysema and lung function. JAMA. 2019;322(6):546-556. doi:10.1001/jama.2019.10255.