摘要：Background Research has shown associations between pediatric asthma outcomes and airborne particulate matter (PM). The importance of particle components remains to be determined. Methods We followed a panel of 45 schoolchildren with persistent asthma living in Southern California. Subjects were monitored over 10 days with offline fractional exhaled nitric oxide (F e NO), a biomarker of airway inflammation. Personal active sampler exposures included continuous particulate matter < 2.5 μm in aerodynamic diameter (PM2.5), 24-hr PM2.5 elemental and organic carbon (EC, OC), and 24-hr nitrogen dioxide. Ambient exposures included PM2.5, PM2.5 EC and OC, and NO2. Data were analyzed with mixed models controlling for personal temperature, humidity and 10-day period. Results The strongest positive associations were between F e NO and 2-day average pollutant concentrations. Per interquartile range pollutant increase, these were: for 24 μg/m3 personal PM2.5, 1.1 ppb F e NO [95% confidence interval (CI), 0.1–1.9]; for 0.6 μg/m3 personal EC, 0.7 ppb F e NO (95% CI, 0.3–1.1); for 17 ppb personal NO2, 1.6 ppb F e NO (95% CI, 0.4–2.8). Larger associations were found for ambient EC and smaller associations for ambient NO2. Ambient PM2.5 and personal and ambient OC were significant only in subjects taking inhaled corticosteroids (ICS) alone. Subjects taking both ICS and antileukotrienes showed no significant associations. Distributed lag models showed personal PM2.5 in the preceding 5 hr was associated with F e NO. In two-pollutant models, the most robust associations were for personal and ambient EC and NO2, and for personal but not ambient PM2.5. Conclusion PM associations with airway inflammation in asthmatics may be missed using ambient particle mass, which may not sufficiently represent causal pollutant components from fossil fuel combustion.
关键词：asthma; epidemiology; exhaled nitric oxide; longitudinal data analysis; nitrogen dioxide; ozone; panel study; particulate air pollution
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