Acute Effects of Outdoor Air Pollution on Emergency Department Visits Due to Five Clinical Subtypes of Coronary Heart Diseases in Shanghai, China

BACKGROUND Air pollution can be a contributing cause to the development and exacerbation of coronary heart disease (CHD), but there is little knowledge about the acute effects of air pollution on different clinical subtypes of CHD. METHODS We conducted a time-series study to investigate the association of air pollution (particulate matter with an aerodynamic diameter < 10 µm [PM10], sulfur dioxide [SO2], and nitrogen dioxide [NO2]) on emergency department (ED) visits due to five different subtypes of CHD in Shanghai, China, from 2010 to 2012. We applied an over-dispersed Poisson generalized addictive model to analyze the associations after controlling for the seasonality, day of the week, and weather conditions. RESULTS We identified a total of 47 523 ED visits for CHD. A 10-µg/m(3) increase in the present-day concentrations of PM10, SO2, and NO2 was associated with respective increases of 1.10% (95% confidence interval [CI] 0.33%-1.87%), 0.90% (95% CI -0.14%-1.93%), and 1.44% (95% CI 0.63%-2.26%) for total ED visits for CHD. These associations varied greatly by clinical type, with strong effects on sudden cardiac death, moderate effects on acute myocardial infarction and angina, weak effects on ischemic cardiomyopathy, and no effect on occult CHD. The associations were stronger among people aged 65 years or more than in younger individuals and in the cool season versus the warm one. CONCLUSIONS Outdoor air pollution may have different effects of air pollution on 5 subtypes of CHD. Our results might be useful for the primary prevention of various subtypes of CHD exacerbated by air pollution.