Fine particulate air pollution and hospital admissions and readmissions for acute myocardial infarction in 26 Chinese cities.

Monitoring data on fine particulate matter (PM 2.5 ) level in China's major cities were available since 2013. We conducted a time-stratified case-crossover study to evaluate the association between short-term exposure to PM 2.5 and hospital admissions for acute myocardial infarction (AMI), as well as subsequent cardiac and AMI readmissions among AMI survivors. Hospital admissions for ST-elevation myocardial infarction (STEMI) and non ST-elevation myocardial infarction (NSTEMI) from 1 January 2014 through 31 December 2015 were identified from electronic Hospitalization Summary Reports. Conditional logistic regression was used to explore the relation between PM 2.5 and hospital admissions for AMI. Individuals discharged alive following STEMI in 2014 were followed up for subsequent readmissions through 31 December 2015. We used the Cox proportional hazards model to evaluate the effect of PM 2.5 pollution on subsequent cardiac and STEMI readmissions. Hospital admissions for STEMI (n = 106,467) and NSTEMI (n = 12,719) were examined separately. Exposure to an interquartile range (IQR) increase in PM 2.5 concentration (47.5 μg/m 3 ) at lags 2, 3, 4 and 0–5 days corresponded with 0.6% (95% CI, 0.1%–1.1%), 0.8 (95% CI, 0.3%–1.3%), 0.6% (95% CI, 0.1%–1.1%) and 0.9% (95% CI, 0–1.8%) increases in STEMI admissions, respectively. For NSTEMI, no significant association was observed with PM 2.5 . We also observed significant associations of PM 2.5 concentration with both subsequent cardiac and STEMI readmissions among STEMI survivors. In conclusion, short-term elevations in PM 2.5 concentration may increase the risk of STEMI but not NSTEMI, and the association appeared to be more evident among STEMI survivors. [ABSTRACT FROM AUTHOR]