2005 Progress Report: Multiple Pollutants and Risk of Emergency Department Visits for Cardiorespiratory Outcomes in AtlantaEPA Grant Number: R829213
Title: Multiple Pollutants and Risk of Emergency Department Visits for Cardiorespiratory Outcomes in Atlanta
Investigators: Tolbert, Paige , Flanders, Dana , Klein, Mitchel , Lyles, Robert , Mulholland, James , Russell, Armistead G. , Ryan, P. Barry , Todd, Knox , Waller, Lance
Current Investigators: Tolbert, Paige , Flanders, Dana , Klein, Mitchel , Lyles, Robert , Metzger, Kristina , Mulholland, James , Peel, Jennifer , Russell, Armistead G. , Ryan, P. Barry , Sarnat, Stefanie Ebelt , Sarnat, Jeremy , Todd, Knox , Waller, Lance
Institution: Emory University
EPA Project Officer: Chung, Serena
Project Period: January 1, 2002 through December 31, 2004 (Extended to December 31, 2006)
Project Period Covered by this Report: January 1, 2005 through December 31, 2006
Project Amount: $1,238,940
RFA: Health Effects of Particulate Matter (2001) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Health Effects , Air
The objective of this research project is to investigate the roles of specific air contaminants, and inter-relationships among them, in producing acute exacerbations of certain cardiac and respiratory conditions . To do this, the study period of an ongoing epidemiologic study will be doubled and multi pollutant questions in the resulting unique and powerful database will be addressed. The study is a time-series investigation of cardiac and respiratory emergency department (ED) visits in relation to daily measures of air quality, including detailed measurements of particulate matter (PM) components being conducted at the station being operated for the Aerosol Research and Inhalation Epidemiology Study (ARIES) in downtown Atlanta. The study period for the previous epidemiologic study, part of the Study of Particulates and Health in Atlanta (SOPHIA) done in conjunction with ARIES, was August 1, 1998, through August 31, 2000. Operation of the ARIES station is being extended an additional 2 years, through August 31, 2002, and we will extend outcome data collection for this period and conduct epidemiologic analysis of the combined data.
Outcome data will be obtained from the 31 hospitals in the metro-Atlanta area participating in the SOPHIA study. Using the diagnostic codes for the visits, multiple cardiac and respiratory case groups will be formed. For each group, time series analysis will be performed to examine the relationship of pollutant levels to daily counts of the outcome. Pollutants of a priori interest being measured at the ARIES station include: the criteria gaseous pollutants, oxygenated hydrocarbons, multiple size fractions of particulate matter (PM)—including PM10, coarse PM, PM2.5, number of ultrafine particles (10-100 nm), and selected components of PM2.5 (sulfates, nitrates, acidity, water-soluble metals, elemental carbon, and organic matter). Control for co-pollutants and assessment of interactions among them will be achieved through standard modeling approaches as well as innovative methods. In addition, the impact of spatial variability on the epidemiological results will be assessed.
With more than 1 million ED visits per year, this study may be the largest study of its type (i.e., single-city ED study with speciated PM data). This investigation will make advances in disentangling effects of PM from the effects of other pollutants and will contribute to our understanding of the effects of exposure to PM in the presence of other pollutants. Moreover, the detailed air quality data available to the proposers will allow assessment of the role of components of PM (e.g., sulfates, water-soluble metals) and size fractions in the multi pollutant analysis.
In Year 3 of the project, we focused on the activities described below.
Acquisition of Data From Metro-Atlanta Hospitals on Emergency Department Visits for the Period 2000-2002 for Use in Our Study
We have compiled data on more than 1 million ED visits for each year of the extended study period (2000-2002). We have received data from 36 of the 40 hospitals that were operating in the period 2000-2002. Two are pending resolution of Health Insurance Portability and Accountability Act of 1996 issues, and one hospital agreed to participate but did not have usable electronic data. Only one hospital declined participation, which is remarkable considering that the project is not a high priority for these institutions.
Editing of New Emergency Department Data
As batches of new data from hospitals were received, we comprehensively checked and edited the data. The task entailed reviewing the data for implausible values and examining distributions to assess whether the data appear reasonable. We also compared data across hospitals and within hospitals for the earlier period and the current period.
Descriptive Analysis of New Air Quality Data
We have assembled air quality data for the extended period 2000-2002 from the Air Quality System (AQS), Assessment of Spatial Aerosol Comparability in Atlanta (ASACA), and the ARIES monitor and have completed descriptive spatial and temporal analyses of these data. In addition, we have conducted intensive work on source apportionment of the available air quality data, which we are currently using in the epidemiologic analysis.
Continued Epidemiologic Analysis of In-House Data
We have conducted extensive epidemiologic analysis of the data we have in-house. The primary approach has entailed time series analysis of air pollutants of a priori interest and visits for specific cardiorespiratory conditions, controlling for long-term trends and meteorology. Further analyses have assessed alternative lag structures; meteorological control; subgroups defined by age, place of residence, and comorbid conditions; the impact of measurement error; and a variety of other questions.
Work on Methodological Issues
We also have been conducting extensive work on modeling issues relating to the time- series air pollution analyses. This work will assist in optimizing the final modeling approach used in the analysis of the study data, as well as having applications to other similar studies.
In the coming year, we will perform final analyses of the data and prepare manuscripts presenting the findings.