Gaseous air pollution and acute myocardial infarction mortality in Hong Kong: A time-stratified case-crossover study

Abstract Acute myocardial infarction (AMI) is a common disease with serious consequences in mortality and morbidity. An association between gaseous air pollution and AMI has been suggested, but the epidemiological evidence is still limited. For the study period 1998–2010, daily counts of AMI deaths were collected, as well as daily air pollution data including concentrations of particulates (PM 10 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), ozone (O 3 ) and carbon monoxide (CO) were also obtained. The associations between gaseous air pollutants and AMI mortality were estimated using time-stratified case-crossover analyses. NO 2 and SO 2 were found to be significantly associated with increased AMI mortality. The odds ratios (ORs) were 1.0455 (95% confidence interval (CI): 1.017–1.0748) and 1.0256 (95% CI: 1.0027–1.0489) for an interquartile range (IQR) increase in the current day's NO 2 and SO 2 concentration, respectively, and this association persisted in 2-pollutant models; and no association was observed for CO and O 3 . It is likely that exposure to elevated ambient NO 2 and SO 2 air pollution contributed to increased AMI mortality.