Ambient air pollution and risk of hospital admission due to acute and chronic coronary syndromes: a time-stratified case-crossover study in the 3 largest urban agglomerations in Poland.

Introduction: Short-term exposure to air pollution may worsen the course of ischemic heart disease (IHD), causing acute and chronic coronary syndromes.

Objectives: This study aimed to assess the risk of hospital admission due to chronic and acute coronary syndromes (ACS) after exposure to various air pollutants in Poland.

Methods: In this time-series study, the risk of hospital admission due to IHD over 3 days from exposure to several air pollutants was evaluated. A distributed lag nonlinear modelling was used to determine the counts of hospital admissions due to chronic and acute coronary syndromes. Data for the 3 largest urban agglomerations in Poland between 2012 and 2017 were collected.

Results: There were 88 467 admissions due to chronic coronary syndromes and 35 403 admissions due to acute coronary syndromes. After accounting adjusting for meteorological variables, the risk of admission due to chronic coronary syndromes increased after the exposure to particulate matter (PM) of aerodynamic diameter no greater than 10 µm (PM10) (cumulative rate ratio per 10 µg/m3, 1.007 [95%CI: 1.002-1.012]), of diameter no greater than 2.5 mm (PM2.5) (1.008 [1.001-1.014]), and nitrogen dioxide (NO2) (1.037 [1.026-1.047]). The risk of admission due to acute coronary syndromes was increased after exposure to PM10 (1.009 [1.002-1.015]) and PM2.5 (1.009 [1.001-1.018]), whereas the association for the gaseous pollutants NO2 and sulfur dioxide was less pronounced: 1.012 (0.998-1.026) and 1.032 (0.998-1.067), respectively.

Conclusion: The exposure to PM10, PM2.5, and NO2 is associated with an increased short-term risk of hospital admission due to acute and chronic coronary syndromes.