Personal Exposure to Particulate Matter Is Associated With Worse Health Perception in Adult Asthma

Background: Epidemiological studies have shown positive associations between particulate matter (PM) air pollution and short-term mortality and morbidity for asthma. The hypothesis that lung inflammation is responsible for these effects has been tested in panel and controlled exposure studies in asthmatic adults, with inconsistent results. Objectives: We investigated whether personal exposure to PM10 and PM2.5 were related to changes in the clinical course of asthma and to lung inflammatory responses in adult asthmatics. Methods: A cohort of 32 asthmatic patients was followed for 2 years. Asthma control test (ACT) and St George's Respiratory Questionnaire (SGRQ) scores, forced expired volume in the first second (FEV1), exhaled nitric oxide (Fe-NO), and pH of exhaled breath condensate (EBC) were determined on 6 occasions during different seasons. Personal exposure to PM was measured for 24 hours prior to clinical assessments. Results: A 10 mu g/m(3) increase in PM10 personal exposure was associated with an increase in SGRQ scores (regression coefficient beta=0.22; 95% confidence interval [CI], -0.005 to 4.451; P=.055) and with a decrease in ACT scores (beta=-0.022; 95% CI, -0.045 to 0.001; P=.060), whereas no associations were found between PM10 and FEV1, Fe-NO, or EBC pH. A positive association was detected between Fe-NO and outdoor O-3 (P=.042) and SO2 (P=.042) concentrations in the subgroup of nonsmoking asthmatics. Conclusions: We concluded that increments in personal exposure to PM10 are associated with a decrease in asthma control and health-related quality of life. However, this study does not provide evidence that 24-hour exposures to PM are associated with short-term changes in lung function or inflammatory responses of the lung.