The Association between Air Quality Index and Risk of Developing ST Segment Elevation Myocardial Infarction: A Case-Crossover Design

Air pollution is one of the most important environmental health threats of our time worldwide, including Iran. Air pollution is a major risk factor threating public health. The overall aim of this study was to determine the relationship between air quality and the incidence of acute myocardial infarction in Tehran.
In this case crossover study, the association between Air Quality Index (AQI) of Tehran and the risk of developing ST-Elevation Myocardial Infarction (STEMI) in patients referring to Tehran Modarres Hospital was investigated during 2 years. Data regarding air quality index were gathered from the Tehran meteorological organization. Air quality index during the 24 hours before STEMI was gathered as case periods and data of air pollutions on one, two and three weeks before the event was collected as control periods. Data analysis was performed using SPSS statistical software. Logistic regression was used to compare air pollutants exposure during case and control periods.
The current study included 208 patients admitted with a diagnosis of STEMI. A positive correlation was detected between average AQI in 24 hours before infarction and STEMI (OR: 1.006; CI: 95%; 1.011-1.001). In other words, for each 10-fold increase in AQI, the risk of STEMI increases by 0.6% for each person. Furthermore, STEMI was increased more significantly in male, people over the age of 60, and diabetic patients according to increase of AQI.
The results of this study showed that air pollution increases the risk of acute myocardial infarction. Thus, more restrictive legislations should be applied to define a safe level of air pollutant production