Association between air pollution and hospital admissions for chronic obstructive pulmonary disease: a time series analysis in Dingxi, China, 2018–2020

Until now, evidence for acute effects of ambient air pollution exposure on hospital admissions for chronic obstructive pulmonary disease (COPD) in the semi-arid Loess Plateau is scarce. We aimed to examine the association between short-term ambient air pollution and daily COPD admissions in Dingxi, China. Daily COPD hospital admissions data during 2018–2020 were acquired from all the tertiary and secondary hospitals in Dingxi. Air pollution and meteorological data over the same periods were also collected. A Poisson generalized additive models (GAM), combined with a distributed lag nonlinear model (DLNM), were employed to evaluate the association between ambient air pollution and hospital admission among patients with COPD. Stratified analyses by gender, age, and season were also performed. Our results showed that PM_2.5, PM₁₀, NO₂, CO, and O₃8 h were associated with COPD-related hospitalizations, and no significant influence of SO₂ was found on COPD hospital admission. When the concentration of PM_2.5 (lag07), PM₁₀ (lag07), NO₂ (lag03), and CO (lag07) increased by 10 μg/m³, the daily number of COPD admissions increased by 11.55% (95%CI, 6.35%, 17.01%), 2.50% (95%CI, 1.04%, 3.99%), 7.17% (95%CI, 0.96%, 13.78%), and 0.46% (95%CI, 0.07%, 0.99%), respectively. Moreover, the associations differed by individual characteristics; the elderly (≥ 65 years) and males were highly susceptible. The effects of PM_2.5, PM₁₀, NO₂, and CO were more obvious in the cold season than in the warm season. This study indicates that exposure to PM_2.5, PM₁₀, NO₂, and CO is associated with COPD hospital admissions.