Abstract
BACKGROUND: This study investigated risks of mortality from and morbidity (emergency room visits (ERVs) and outpatient visits) of asthma and chronic obstructive pulmonary disease (COPD) associated with extreme temperatures, fine particulate matter (PM2.5), and ozone (O3) by sex, and age, from 2005 to 2016 in 6 metropolitan cities in Taiwan. METHODS: The distributed lag non-linear model was employed to assess age (0-18, 19-39, 40-64, and 65 years and above), sex-cause-specific deaths, ERVs, and outpatient visits associated with extreme high (99th percentile) and low (5th percentile) temperatures and PM2.5 and O3 concentrations at 90th percentile. Random-effects meta-analysis was adopted to investigate cause-specific pooled relative risk (RR) and 95% confidence intervals (CI) for the whole studied areas. RESULTS: Only the mortality risk of COPD in the elderly men was significantly associated with the extreme low temperatures. Exposure to the 90th percentile PM2.5 was associated with outpatient visits for asthma in 0-18 years old boys [RR = 1.15 (95% CI: 1.09-1.22)]. Meanwhile, significant elevation of ERVs of asthma for females aged 40-64 years was associated with exposure to ozone, with the highest RR of 1.21 (95% CI: 1.05-1.39). CONCLUSIONS: This study identified vulnerable subpopulations who were at risk to extreme events associated with ambient environments deserving further evaluation for adaptation.