Short-term PM2.5 exposure and mortality in older adults with asthma in South Korea

BACKGROUND: Despite growing concerns over the adverse health effects of air pollution, research on the mortality risk associated with exposure to fine particulate matter (PM) in older adults with asthma remains limited. This study aims to investigate the association between short-term exposure to PM2.5 and mortality risk among older adults with asthma. METHODS: This study utilized the National Health Insurance Service database in South Korea and included 139 189 individuals aged 65 and older with asthma who died between 2015 and 2021. A time-stratified case-crossover design was applied to assess the short-term effects of air pollution exposure on mortality. The daily average PM2.5 concentrations were calculated for case and referent dates. Conditional logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for mortality across quartiles of PM2.5 exposure, adjusting for environmental variables and holidays. RESULTS: The highest quartile of PM2.5 exposure (lag 0) was associated with a higher odds ratio for mortality (aOR 1.048, 95% CI 1.020-1.076, p for trend = .024) compared to the lowest quartile. Similar trends were observed for lag 1 (aOR 1.032, 95% CI 1.005-1.060, p for trend = .015) and lag 0-1 (aOR 1.022, 95% CI 0.994-1.051, p for trend = .009). CONCLUSION: This study provides epidemiological evidence of an association between short-term exposure to PM2.5 and an increased mortality risk among older adults with asthma. These findings highlight the need for targeted preventive management strategies to mitigate health risks associated with short-term PM2.5 exposure, particularly for those vulnerable to air pollution.