Abstract
ISEE-272 Introduction: No study has looked at fine versus coarse particle health effects on asthmatic children (PM2.5 vs. PM2.5-10). Few non-invasive biomarkers of asthma morbidity have been evaluated for their implementation into field epidemiological studies. We performed a panel study to address these scientific gaps. Aim: The purpose of this study was two-fold: 1.) to test biomarkers of asthma morbidity for their potential application in larger field epidemiological studies and 2.) to test the hypothesis that there were differences in persistent asthmatic children's responses to fine and coarse particulate air pollution. Methods: We performed a panel study of the health effects of PM<2.5 and PM2.5-10 on asthmatic children using an observation period, including peak particle season and excluding peak ozone season. From September 2003 through May 2004, we enrolled 28 persistent asthmatic children from the Chapel Hill area into a 6-week panel study. Each child was 8-18 years old and had one comprehensive clinical evaluation (2-3 hr), one panel enrollment (45 min.), and one panel completion (10 min.) visit at the US EPA's Human Studies Facility in Chapel Hill, North Carolina. The clinical evaluation included a medical history, vital signs, physical exam, spirometry, buccal swab, allergy skin test, nasal lavage, collection of exhaled breath condensates, exhaled nitric oxide measurement, urine collection, and blood draw. Children were provided with an electronic peak flow meter for twice daily peak expiratory flow assessment, and a personal digital assistant/mobile telephone for internet-based daily health diary collection, upon enrollment. Daily PM<2.5 and PM2.5-10 measurements were made concurrently using a centrally located dichotomous air sampler on the roof of the Human Studies Facility, from August 2003 through June 2004. Results: Most study children were moderate persistent asthmatics (18, 64%), with four severe persistent, five mild persistent, and only two mild intermittent. All 28 children completed the entire 6-week panel. Children were on study for an average of 42 days (+/− 1.8 days) with an 85% diary and 89% peak flow meter completion average. Eighteen of the 28 children consented to the blood draw (64%). The mean daily PM<2.5 and PM2.5-10 measurements were 11.3 (Interquartile range: 8.1) and 5.6 (Interquartile range: 4.6), respectively. A sub-group of 18 children had supplemental outdoor monitoring performed at their residence for up to five consecutive days. Particulate air pollution levels were consistently below the standards set by the USEPA. Conclusion: We successfully evaluated, enrolled, and retained persistent asthmatic children within a 6-week daily diary study with good compliance. This study demonstrates that persistent asthmatic children can provide reasonably complete daily diary and peak expiratory flow data for up to six weeks using the technology employed in our study. These findings do not necessarily represent United States Environmental Protection Agency policy.
Published Version
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