PROJECT 6. A Prospective Study of Asthma Susceptibility to PM: Epidemiologic Investigations of Key PM Components and Biomarkers of Effects.

PI: G.D. Thurston; Co-I.: J. Reibman.

The objective of this research is to exploit available data from a comprehensive ongoing PM characterization field study to investigate by which component(s) of PM are asthmatics most strongly affected, and by what mechanism(s)? We will study a cohort of 30 inner city adult patients with moderate to severe asthma from the Bellevue Hospital Primary Care Asthma Clinic (BHPCAC), directed by Dr. Reibman. Individual daily determinations of asthma symptoms, lung function, medication usage, and activities, as well as biological marker levels (in nasal lavage and serum) will be obtained on days following PM episodes. Daily PM measurements collected at a nearby central monitoring site are being augmented by much more extensive PM component characterization data to be collected at this site as part of an intensive PM air monitoring-hospital visit study continuing into 2000, including PM₁₀, PM_2.5, H⁺, sulfate, elemental and organic carbon, trace elements, and pollens and spore counts. Further, Dr. Lippmann will be conducting daily ultrafine particle counts at this site as part of a separately funded EPA personal sampling project.

The study cohort will be followed by prospective monitoring of their health, and by an evaluation of the effects of ambient elevations of PM on subject health status (i.e., daily diary records of peak flow, symptoms, medication use during study periods). We will also evaluate baselines (during a low PM exposure period) of health, spirometry, and serum and nasal lavage levels of proinflammatory mediators (IL-6, IL-8), as well as of Th1 and Th2 induced cells (interferon-gamma and IL-4, respectively) that are thought to mediate asthma response. Alterations in biomarker levels will be determined on several days for each subject on days following PM days exceeding the historical 80th %ile of PM10, as procured from continuous TEOM measurements of PM10 mass from the nearby air monitoring site.

Time-series analyses will be applied to evaluate the associations between asthma health and the various PM air pollution components during this study, in order to evaluate the extent to which each participant acutely responds to PM. Individual-level personal and biological data will be obtained that will allow for the control of age, sex, race, activities, etc. Statistical comparisons of these results across the various PM components (e.g., fine vs. coarse mass, elemental concentrations, ultrafine aerosol measurements) will allow an evaluation of their relative associations with adverse health effects in asthmatics.