Effects of Air Pollution on Elderly All Respiratory, COPD, and Pneumonia Mortality and Hospital Admissions

Abstract

ISEE-221 Objective: Respiratory mortality and hospital admissions have been associated with particulate and gaseous air pollutants in epidemiologic studies. We investigated for the first time the short-term effects of ambient ultrafine particles (<0.1 μm) and source-specific fine particles (PM2.5, <2.5μm) on cause-specific respiratory mortality and hospital admissions. Material and Methods: Daily levels of ultrafine particles, PM2.5, CO, NO2, and O3 were measured at central outdoor measurement sites during 1998 to 2004. The daily mortality and hospital admission counts of the elderly (≥65) for all-respiratory diseases (ICD 10: J00-J99), chronic obstructive pulmonary disease (COPD: J41, J44), and pneumonia (J12-J15, J16.8, J18) were obtained from national registers. For analyses we used Poisson regression and the generalized additive model in R. EPA-positive matrix factorization was used for the source apportionment of PM2.5. Four sources were identified: traffic, soil, coal combustion, and secondary particles. Results: There were a total of 26,095 all-respiratory, 6937 COPD, and 10,733 pneumonia hospital admissions, and 3701 all-respiratory, 1103 COPD, and 2169 pneumonia deaths. Mean ultrafine particle and PM2.5 levels were 9273 cm−3 and 9.5 μg/m3, respectively. Two-day mean of PM2.5 was associated with all-respiratory [1.9% (95% CI, 0.58–3.24)], COPD [2.7% (95% CI, 0.22–5.2)], and pneumonia [2.2% (95% CI, 0.22–4.2)] admissions. Carbon monoxide was associated with all-respiratory admissions over the 2-day mean [2.4% (95% CI, 0.8–4.0)]. Ultrafine particles were associated with all-respiratory and pneumonia admissions at 1-day lag, but associations were less consistent. All-respiratory and COPD mortality were positively associated with the same-day O3 levels. Of the PM2.5 sources, traffic was positively associated with all-respiratory and pneumonia admissions, and secondary particles with COPD mortality and admissions. Conclusions: Fine particles, at low levels, are associated with hospital admissions for respiratory diseases, COPD, and pneumonia among elderly persons.