Association between Atmospheric Fine Particulate Matter and Hospital Admissions for Chronic Obstructive Pulmonary Disease in Southwestern Taiwan: A Population-Based Study

Objectives : This paper reports on the findings of a population-based study to evaluate the relationship between atmospheric fine particulate matter (PM 2.5 ) levels and hospital admissions for chronic obstructive pulmonary disease (COPD) in southwestern Taiwan over a three-year period, 2008–2010. Methods : Data on hospital admissions for COPD and PM 2.5 levels were obtained from the National Health Insurance Research database (NHIRD) and the Environmental Protection Administration from 2008 to 2010, respectively. The lag structure of relative risks (RRs) of hospital admissions for COPD was estimated using a Poisson regression model. Results : During the study period, the overall average hospitalization rate of COPD and mean 24-h average level of PM 2.5 was 0.18% and 39.37 μg/m 3 , respectively. There were seasonal variations in PM 2.5 concentrations in southwestern Taiwan, with higher PM 2.5 concentrations in both spring (average: 48.54 μg/m 3 ) and winter (49.96 μg/m 3 ) than in summer (25.89 μg/m 3 ) and autumn (33.37 μg/m 3 ). Increased COPD admissions were significantly associated with PM 2.5 in both spring (February–April) and winter (October–January), with the relative risks (RRs) for every 10 μg/m 3 increase in PM 2.5 being 1.25 (95% CI = 1.22–1.27) and 1.24 (95% CI = 1.23–1.26), respectively, at a lag zero days ( i.e. , no lag days). Lag effects on COPD admissions were observed for PM 2.5 , with the elevated RRs beginning at lag zero days and larger RRs estimates tending to occur at longer lags (up to six days, i.e. , lag 0–5 days). Conclusions : In general, findings reveal an association between atmospheric fine particulate matter (PM 2.5 ) and hospital admissions for COPD in southwestern Taiwan, especially during both spring and winter seasons.