Evaluation of Air Pollution Effects on Cardiovascular Hospital Admissions in Tabriz: A Case-Crossover Analysis

Abstract

Background & Objectives: In recent years, associations between air pollution and cardiovascular diseases have been reported around the world. However, a few studies have been conducted in industrial megacities which face air pollution in Iran. This study aimed to determine the association between air pollution and hospital admissions for cardiovascular diseases in Tabriz. Materials & Methods: We applied a case-crossover analysis to compute associations between daily concentrations of air pollutants including NO2, SO2, CO, PM10 and O3 and hospital admissions for cardio-vascular diseases. Daily hospital admission data from 2009 to 2011 were collected from five hospitals in Tabriz. Air quality data for the study period were obtained from the six fixed online air quality monitoring stations operated by Tabriz Air Quality Control Center. The daily mean temperature and relative humidity data for the same period were obtained from East Azerbaijan Meteorological Bureau. Results: From the 1512 cases, the data of 753 cases were used in our analysis. The results of ANNs with importance analysis showed that the most important causes of hospital admissions due to I20 were O3, SO2, NO and PM10, for I21 were SO2, NO and NO2 and for I20.9 were O3, SO2, NO and NO2. According to the results, the air pollutants had greater adverse effects on females and older cases. Conclusions: The results of this study showed that gaseous air pollutants including SO2, NO and O3 had the greatest effects on hospital admissions for cardiovascular diseases and significant effects on females and older people.