Association between short-term exposure to ambient PM and its components with hospital admissions for patients with coronary heart disease and comorbid diabetes mellitus in Beijing, China.

Existing researches had primarily investigated the associations between various air pollutants and the risk of coronary heart disease (CHD) or diabetes mellitus (DM) separately. However, the significance and effects of PM and its components in patients with CHD and comorbid DM (CHD-DM) remain unclear. Patient data was sourced from the Beijing Municipal Health Commission Information Centre between January 1, 2014, and December 31, 2018. We utilized Generalized Additive Models (GAM) to analyze the relationship between daily hospital admissions for CHD-DM patients and PM exposure. The hospital admissions were treated as count data, offset by the total CHD-DM population, with a logarithmic link function. Smooth functions were included to account for the non-linear effects of time trends and meteorological factors used in both Chinese and WHO air quality guidelines. In Beijing, records show 215,267 hospital admissions for patients with CHD-DM. Every 10 μg/m increase of particles with an aerodynamic diameter ≤2.5 μm (PM) corresponded to a 0.62% (95%CI: 0.49 to 0.76) increment for CHD-DM patients' admissions. As for the PM components: Per 10 μg/m increase of SO was 2.31% (95%CI: 1.51 to 3.11), NO was 3.35% (95%CI: 2.47 to 4.23), for NH the percentage change value was 4.37% (95%CI: 2.99 to 5.77), for OM was 5.36% (95%CI: 4.19 to 6.55), for BC was 36.51% (95%CI: 28.09 to 45.47) increment for CHD-DM patients' admissions. Based on the WHO 2021 air quality guideline, our estimation suggests that a reduction in PM concentrations could prevent approximately 2.62% (95%CI: 2.04%-3.2%) hospital admissions, corresponding to 5632 (95%CI: 4397 to 6879) CHD-DM patients, could be avoidable. Patients with CHD-DM who were exposed to PM and its components had an increased risk of hospital admissions. Furthermore, among all PM components, BC may be the most significant contributor to the association between PM and hospital admissions among CHD-DM patients.