Attributable risk of cardiovascular hospital admissions due to coarse particulate pollution: A multi-city time-series analysis in southwestern China

Abstract

Few studies have evaluated the morbidity burden of cardiovascular diseases (CVDs) due to coarse particulate matter (PMC, particles with an aerodynamic diameter between 2.5 and 10 μm) pollution, especially in a multi-city setting. This study aimed to investigate the short-term impacts of PMC on hospital admissions (HAs) for total and cause-specific CVDs in 18 cities of Sichuan Province, Southwestern China during 2015–2016, and calculate the corresponding attributable risks. First, generalized additive model (GAM) was employed to estimate the city-specific associations of PMC with CVDs hospitalizations, and then combined the results from the single cities to obtain the pooled effects at the regional level. Age-, sex- and season-specific analyses were also performed. We further estimated the burden of HAs for CVDs attributable to PMC exposure. A total of 621,835 HAs for CVDs were collected during the study period. We found that PMC was significantly associated with elevated risks of CVDs hospitalizations. Per 10 μg/m3 increase in PMC corresponded to an increase of 1.18% (95% CI: 0.67%–1.68%) in daily HAs for CVDs. For specific subtypes of CVDs, significant associations of PMC with acute myocardial infarction, heart failure and ischemic stroke were observed. The effect estimates of PMC remained robust after adjusting for PM2.5 (particles with an aerodynamic diameter ≤ 2.5 μm) and gaseous pollutants in co-pollutant models. The pernicious effects were found to be stronger in the elderly and in the warm season. Overall, about 1.26% (95% CI: 0.73%–1.79%) of HAs for CVDs could be attributable to PMC exposure, corresponding to 7863 (95% CI: 4554–11110) attributable CVDs HAs. Our findings suggest that PMC might result in increased risk of HAs for CVDs in Sichuan Province, Southwestern China, and should be considered in the prevention and control of CVDs.