Urban air pollution and chronic obstructive pulmonary disease-related emergency department visits.
BACKGROUND
Patients with chronic obstructive pulmonary disease (COPD) can have recurrent disease exacerbations triggered by several factors, including air pollution. Visits to the emergency respiratory department can be a direct result of short-term exposure to air pollution. The aim of this study was to investigate the relationship between the daily number of COPD emergency department visits and the daily environmental air concentrations of PM(10), SO(2), NO(2), CO and O(3) in the City of São Paulo, Brazil.


METHODS
The sample data were collected between 2001 and 2003 and are categorised by gender and age. Generalised linear Poisson regression models were adopted to control for both short- and long-term seasonal changes as well as for temperature and relative humidity. The non-linear dependencies were controlled using a natural cubic spline function. Third-degree polynomial distributed lag models were adopted to estimate both lag structures and the cumulative effects of air pollutants.


RESULTS
PM(10) and SO(2) readings showed both acute and lagged effects on COPD emergency department visits. Interquartile range increases in their concentration (28.3 microg/m(3) and 7.8 microg/m(3), respectively) were associated with a cumulative 6-day increase of 19% and 16% in COPD admissions, respectively. An effect on women was observed at lag 0, and among the elderly the lag period was noted to be longer. Increases in CO concentration showed impacts in the female and elderly groups. NO(2) and O(3) presented mild effects on the elderly and in women, respectively.


CONCLUSIONS
These results indicate that air pollution affects health in a gender- and age-specific manner and should be considered a relevant risk factor that exacerbates COPD in urban environments.
Arbex
M A
MA
Internal Medicine Post- Graduate Programme, São Paulo Federal University, Medical School, São Paulo, Brazil. arbexma@techs.com.br
de Souza Conceição
G M
GM
Cendon
S P
SP
Arbex
F F
FF
Lopes
A C
AC
Moysés
E P
EP
Santiago
S L
SL
Saldiva
P H N
PH
Pereira
L A A
LA
Braga
A L F
AL
D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects*; D001938:Brazil; D002248:Carbon Monoxide / Q000633:toxicity; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000633:toxicity; D010126:Ozone / Q000633:toxicity; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D018570:Risk Assessment; D013458:Sulfur Dioxide / Q000633:toxicity; D014504:Urban Health / Q000706:statistics & numerical data
D000393:Air Pollutants; D013458:Sulfur Dioxide; D009569:Nitric Oxide; D010126:Ozone; D002248:Carbon Monoxide