Short-term effects of low-level air pollution on respiratory health of adults suffering from moderate to severe asthma

Only a few studies have been carried out on the health effects of air pollution on patients suffering from severe asthma. We wanted to test the sensitivity of these patients to Paris air pollution. During 13 months, 60 severe asthmatics (62% female; mean age 55 years) were monitored by their physician, who filled in a follow-up form at each consultation and reported any asthma attacks. Daily levels of SO2, PM10, NO2, and )(3) were provided by the air quality network. Statistical analysis (generalized estimating equation models that accounted for autocorrelation of responses, temporal, meteorological, and aerobiological variables, and some individual characteristics) revealed significant associations between PM10, O-3 and incident asthma attacks. Odds Ratio (OR) for an increase of 10 mug/m(3) of PM10 was 1.41; 95% confidence interval (CI) [1.16; 1.71]. An increase of 10 mug/m(3) of O-3 was significantly associated with asthma attacks; OR = 1.20; 95% Cl [1.03; 1.41]. These relations were observed after a delay between exposure and asthma attacks of 3 to 5 days for PM10 and 2 days for 03, and they tended to differ according to atopic status. The results of our study suggest that ambient Paris levels of PM10 and 03 affected health of severe asthmatics, despite their treatment. (C) 2002 Elsevier Science (USA).