Changes in air pollutant concentrations up risk of small airway dysfunction

The combined effect of annual changes in the concentrations of several air pollutants appear to elevate the risk of small airway dysfunction (SAD), suggests a study.

Analysis was carried out in a total of 29,115 individuals, who were identified using the Korea National Health and Nutrition Examination Survey (KNHANES) V–VIII database from 2010 to 2018.

SAD was significantly associated with the quartiles of annual changes in the following air pollutants: NO₂ (odds ratio [OR], 1.10, 95 percent confidence interval [CI], 1.08–1.12), O₃ (OR, 1.03, 95 percent CI, 1.00–1.05), PM_2.5 (OR, 1.03, 95 percent CI, 1.00–1.05), SO₂ (OR, 1.04, 95 percent CI, 1.02–1.08), and CO (OR, 1.16, 95 percent CI, 1.12–1.19).

The combined effect of annual air pollutant changes showed a significant association with SAD irrespective of smoking (OR, 1.31, 95 percent CI, 1.26‒1.35; p<0.001). This trend persistent across the entire study population and various subgroup populations.

A team of investigators analysed the KNHANES V‒VIII databases to explore the relationship between annual changes in air pollutants over a 5-year period and small airway function. They estimated the annual concentrations of NO₂, O₃, PM_2.5, SO₂ and CO. SAD was defined as forced expiratory flow between 25 percent and 75 percent of the vital capacity (FEF_25%–75%) <65 percent.

Finally, the investigators measured the combined effect of the annual changes in multiple air pollutants using the quantile generalized computation model.