How air pollution influences clinical management of respiratory diseases. A case-crossover study in Milan.
BACKGROUND
Environmental pollution is a known risk factor for multiple diseases and furthermore increases rate of hospitalisations. We investigated the correlation between emergency room admissions (ERAs) of the general population for respiratory diseases and the environmental pollutant levels in Milan, a metropolis in northern Italy.


METHODS
We collected data from 45770 ERAs for respiratory diseases. A time-stratified case-crossover design was used to investigate the association between air pollution levels and ERAs for acute respiratory conditions. The effects of air pollutants were investigated at lag 0 to lag 5, lag 0-2 and lag 3-5 in both single and multi-pollutant models, adjusted for daily weather variables.


RESULTS
An increase in ozone (O(3)) levels at lag 3-5 was associated with a 78% increase in the number of ERAs for asthma, especially during the warm season. Exposure to carbon monoxide (CO) proved to be a risk factor for pneumonia at lag 0-2 and in the warm season increased the risk of ERA by 66%. A significant association was found between ERAs for COPD exacerbation and levels of sulphur dioxide (SO(2)), CO, nitrate dioxide (NO(2)), and particulate matter (PM(10) and PM(2.5)). The multipollutant model that includes all pollutants showed a significant association between CO (26%) and ERA for upper respiratory tract diseases at lag 0-2. For chronic obstructive pulmonary disease (COPD) exacerbations, only CO (OR 1.19) showed a significant association.


CONCLUSIONS
Exposure to environmental pollution, even at typical low levels, can increase the risk of ERA for acute respiratory diseases and exacerbation of obstructive lung diseases in the general population.
Dipartimento di Scienze della Salute, Università degli Studi di Milano, Respiratory Unit, San Paolo Hospital, Milan, Italy.
Pierachille
P
Santus
Antonio
A
Russo
Enzo
E
Madonini
Luigi
L
Allegra
Francesco
F
Blasi
Stefano
S
Centanni
Antonio
A
Miadonna
Gianfranco
G
Schiraldi
Sandro
S
Amaducci
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000397:Air Pollution / Q000706:statistics & numerical data*; D016022:Case-Control Studies; D015984:Causality; D002648:Child; D002675:Child, Preschool; D018592:Cross-Over Studies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012120:Respiration Disorders / Q000453:epidemiology*; D012307:Risk Factors; D012621:Seasons; D055815:Young Adult