Abstract
Short-term effects of air pollutants on respiratory mortality and morbidity have been consistently reported but usually studied separately.
To more completely assess air pollution effects, we studied hospitalisations for respiratory diseases together with out-of hospital respiratory deaths.
A “time-stratified” case-crossover study was carried out in six Italian cities from 2001–2005. Associations between daily particulate matter (PM10) and nitrogen dioxide (NO2) and hospitalisations for respiratory diseases (n. 100,690), chronic obstructive pulmonary disease (COPD) (n. 38,577), lower respiratory tract infections (LRTI) among COPD patients (n. 9,886) and out-of-hospital respiratory deaths (n 5,490) were estimated for 35+year-old residents.
For 10 μg·m−3 PM10, we found an immediate 0.59% (lag 0–1) increase in hospitalisations for respiratory diseases and a 0.67% increase for COPD; the 1.91% increase in LRTI hospitalisations lasted longer (lag 0–3) and the 3.95% increase in respiratory mortality lasted six days. Effects of NO2 were stronger and lasted longer (lag 0–5). Age, gender, and previous ischemic heart disease acted as effect modifiers for different outcomes.
Analysing multiple more than single respiratory events shows stronger air pollution effects. The temporal relationship between the pollutants' increases and hospitalizations or mortality for respiratory diseases differs.
- Air pollutants
- case-crossover design
- multi-city study
- nitrogen dioxide
- particulate matter
- respiratory hospitalisations
- respiratory mortality
- ERS