氣候變遷、空氣污染與慢性阻塞性肺病的關係

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality worldwide. Beyond traditional risk factors such as smoking, emerging evidence suggests that climate change and air pollution substantially influence COPD outcomes. Variations in temperature and relative humidity (RH), coupled with elevated levels of fine particulate matter (PM2.5), may exacerbate symptom severity, accelerate disease progression, and increase mortality rates. However, the interplay between these environmental factors and COPD, as well as the underlying mechanisms, remains insufficiently understood. This thesis aimed to (1) assess the long-term relationship between climate change, represented by deviations in temperature and RH, and COPD mortality at the global and national levels, (2) examine the short-term impacts of climatic variables and PM2.5 exposure on COPD severity among individual patients, and (3) elucidate whether PM2.5 mediates the associations between temperature, RH, and COPD pathophysiological outcomes, including emphysema severity. First, age-standardized COPD mortality data from 185 countries (2000–2018) were analyzed to evaluate the effects of temperature and RH deviations, along with PM2.5 concentrations, using mixed-effect regression models. Next, a cross-sectional study of COPD patients in northern Taiwan assessed how short-term (1-, 7-, and 30-day) changes in RH, temperature, and PM2.5 correlated with lung function measures, symptom scores, and exacerbation frequency. Finally, a mechanistic investigation using chest CT imaging (% low attenuation area), lung function tests, and blood biomarkers in COPD patients explored the mediating role of PM2.5 in linking long-term (1-, 3-, and 5-year) exposures to climatic variables with emphysema severity and oxygen desaturation. Globally, COPD mortality rates were lower where socio-demographic conditions improved and smoking prevalence declined, yet remained significantly influenced by climate and pollution. Decreased temperature deviations and increased RH were associated with higher COPD mortality, while incremental rises in annual PM2.5 levels further elevated this risk. At the patient level, short-term exposure to low RH, extreme temperatures, and elevated PM2.5 concentrations was associated with deteriorations in lung function, greater symptom burdens, and increased exacerbation frequency. Moreover, PM2.5 emerged as a key mediator: decrease in temperature and changes in RH impacted emphysema severity and oxygen saturation partly through PM2.5-related inflammatory and oxidative stress pathways. This thesis provides evidence that climate variability and PM2.5 pollution influence COPD outcomes. Long-term climate deviations are linked to heightened COPD mortality, while short-term fluctuations in temperature, RH, and PM2.5 intensify symptom severity and disease progression. The mediating role of PM2.5 offers new insights into underlying mechanisms, underscoring the importance of integrated environmental and clinical strategies. Mitigating PM2.5 levels, improving air quality, and adapting healthcare interventions to climate patterns are crucial steps to reduce COPD burdens in an era of global environmental change.