Association between short-term exposure to PM2.5 and mortality in adults with dyslipidemia and asthma: a time-stratified case-crossover study in South Korea

The harmful effects of particulate matter (PM) on health are well-documented, and recent studies have increasingly focused on its impact on vulnerable populations. While PM exposure is known to affect both lipid levels and asthma exacerbation, its impact on mortality risk in individuals with coexisting dyslipidemia and asthma has not been well studied, despite evidence linking these two conditions.

Using the National Health Insurance Service (NHIS) database, we identified 51,833 patients with dyslipidemia and newly diagnosed asthma who died between January 1, 2015, and December 31, 2021. The study period spanned January 1, 2009, to December 31, 2021, for baseline data collection. The association between short-term PM_2.5 exposure and mortality was analyzed with conditional logistic regression using a time-stratified case-crossover design.

Short-term PM_2.5 exposure was significantly associated with increased mortality risk among individuals with dyslipidemia and newly diagnosed asthma. Across various lag periods and models, the odds ratio per 10 μg/m³ increase in PM_2.5, with consistent trends of statistical significance (p-trend <0.05).

This study is the first to demonstrate that increased short-term exposure to PM_2.5 elevates mortality risk in patients with comorbid dyslipidemia and asthma. Efforts to reduce PM_2.5 emissions and establish systematic PM concentration alert systems are expected to improve health outcomes for these patients.