Association Between PM10 and O3 Levels and Hospital Visits for Cardiovascular Diseases in Bangkok, Thailand

BACKGROUND The association between air pollution and cardiovascular diseases is well known, but previous studies only assessed mortality and hospital admissions in North America, Europe, and Northeast Asia. Few studies have been conducted in less-developed countries in regions with a tropical climate. This study evaluated whether short-term exposures to fine particulate matter (PM(10)) and ozone (O(3)) were associated with hospital visits for cardiovascular diseases (CVD; ICD-10th, I00-I99) in central Bangkok, Thailand. METHODS Data from hospital records were obtained from 3 major government hospitals. All hospital visits were stratified by age group and category of CVD. Daily PM(10) and O(3) levels reported by the Pollution Control Department from April 2002 to December 2006 (1736 days) were used in a time-series analysis with a generalized additive model procedure. RESULTS Exposure on the previous day to PM(10) and O(3) had a positive association with hospital visits for CVD among elderly (>or=65 years) individuals. The increase in CVD hospital visits in this age group was 0.10% (95% CI, 0.03-0.19) with a 10 microg/m(3) increase in PM(10), and 0.50% (95% CI, 0.19-0.81) with an increase in O(3). CONCLUSIONS In central Bangkok, a short-term association was observed between increases in daily levels of PM(10) and O(3) and the number of daily emergency hospital visits for CVD, particularly among individuals aged >or=65 years.