Short-term exposure to ambient air pollution and hospital admissions for angina among older adults in South China

Ambient air pollution has been linked to an increased risk of various acute cardiovascular outcomes; however, its effects on hospital admissions for angina are yet to be evaluated. We conducted a time-stratified case-crossover study with conditional logistic regression models among 46,687 adults 60 years or older who were admitted to hospital for angina in Guangzhou, China during 2016-2019 to investigate the association of exposure to ambient particulate matter with an aerodynamic diameter <= 2.5 mu m (PM2.5), particulate matter with an aerodynamic diameter <= 10 mu m (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O-3) with hospital admissions for angina. Daily residential air pollutant exposures were extracted from a grid dataset. Each 10 mu g/m(3) increase of lag 0-day exposure to PM10, SO2, NO2, CO, and O-3 was significantly associated with a 0.80% (95% confidential interval: 0.32%, 1.28%), 4.04% (0.34%, 7.89%), 2.47% (1.81%, 3.12%), 0.13% (0.07%, 0.19%), and -0.38% (-0.74%, -0.01%) increase in odds of admission, respectively. The association for NO2 exposure remained stable, while the associations for PM10, SO2, CO, and O-3 became insignificant with adjustment for other air pollutants. The association for NO2 exposure was stronger in cool season. We estimated that up to 9.12% of angina admissions were attributable to NO2 exposure. Our findings suggest that ambient NO2 may trigger hospital admissions for angina in Chinese older adults, which highlights the importance to prevent angina by reducing individual NO2 exposures.