Ambient particulate matter and chronic obstructive pulmonary disease mortality: a nationwide, individual-level, case-crossover study in China.

Abstract

Background: Short-term exposure to particulate matter air pollution has been associated with the exacerbations of COPD, but its association with COPD mortality was not fully elucidated. We aimed to assess the association between short-term particulate matter exposure and the risk of COPD mortality in China using individual-level data.

Methods: We derived 2.26 million COPD deaths from a national death registry database in Chinese mainland between 2013 and 2019. Exposures to fine particulate matter (PM_2.5) and coarse particulate matter (PM_2.5-10) were assessed by satellite-based models of a 1 × 1 km resolution and assigned to each individual based on residential address. The associations of PM_2.5 and PM_2.5-10 with COPD mortality were examined using a time-stratified case-crossover design and conditional logistic regressions with distributed lag models. We further conducted stratified analyses by age, sex, education level, and season.

Findings: Short-term exposures to both PM_2.5 and PM_2.5-10 were associated with increased risks of COPD mortality. These associations appeared and peaked on the concurrent day, attenuated and became nonsignificant after 5 or 7 days, respectively. The exposure-response curves were approximately linear without discernible thresholds. An interquartile range increase in PM_2.5 and PM_2.5-10 concentrations was associated with 4.23% (95% CI: 3.75%, 4.72%) and 2.67% (95% CI: 2.18%, 3.16%) higher risks of COPD mortality over lag 0-7 d, respectively. The associations of PM_2.5 and PM_2.5-10 attenuated slightly but were still significant in the mutual-adjustment models. A larger association of PM_2.5-10 was observed in the warm season.

Interpretation: This individual-level, nationwide, case-crossover study suggests that short-term exposure to PM_2.5 and PM_2.5-10 might act as one of the environmental risk factors for COPD mortality.

Funding: This study is supported by the National Key Research and Development Program of China (2023YFC3708304 and 2022YFC3702701), the National Natural Science Foundation of China (82304090 and 82030103), the 3-year Action Plan for Strengthening the Construction of the Public Health System in Shanghai (GWVI-11.2-YQ31), and the Science and Technology Commission of Shanghai Municipality (21TQ015).