Personal exposure to air pollution and respiratory health of COPD
patients in London
Evangelopoulos, Dimitris
Chatzidiakou, Lia
Walton, Heather and
Katsouyanni, Klea
Kelly, Frank J.
Quint, Jennifer K.
Jones,
Roderic L.
Barratt, Benjamin
Previous studies have investigated the effects of air pollution on
chronic obstructive pulmonary disease (COPD) patients using either fixed
site measurements or a limited number of personal measurements, usually
for one pollutant and a short time period. These limitations may
introduce bias and distort the epidemiological associations as they do
not account for all the potential sources or the temporal variability of
pollution.
We used detailed information on individuals’ exposure to various
pollutants measured at fine spatio-temporal scale to obtain more
reliable effect estimates. A panel of 115 patients was followed up for
an average continuous period of 128 days carrying a personal monitor
specifically designed for this project that measured temperature, PM10,
PM2.5, NO2, NO, CO and O-3 at one-minute time resolution. Each patient
recorded daily information on respiratory symptoms and measured peak
expiratory flow (PEF). A pulmonologist combined related data to define a
binary variable denoting an “exacerbation”. The exposure-response
associations were assessed with mixed-effects models.
We found that gaseous pollutants were associated with a deterioration in
patients’ health. We observed an increase of 16.4% (95% confidence
interval: 8.6-24.6%), 9.4% (5.4-13.6%) and 7.6% (3.0-12.4%) in the
odds of exacerbation for an interquartile range increase in NO2, NO and
CO respectively. Similar results were obtained for cough and sputum. O-3
was found to have adverse associations with PEF and breathlessness. No
association was observed between particles and any outcome.
Our findings suggest that, when considering total personal exposure to
air pollutants, mainly the gaseous pollutants affect COPD patients’
health.
(EN)
