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An Analysis of Childhood Asthma and Environmental Exposures in Utah. Michelle Gillette, M.P.H. Office of Epidemiology Utah Department of Health. Asthma in the United States. Increasing prevalence in all age, sex, and racial groups (NHLBI Data Fact Sheet, 1999).
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An Analysis of Childhood Asthma and Environmental Exposures in Utah Michelle Gillette, M.P.H. Office of Epidemiology Utah Department of Health
Asthma in the United States Increasing prevalence in all age, sex, and racial groups (NHLBI Data Fact Sheet, 1999)
Trends in Asthma Prevalence by Age Age National Heart, Lung and Blood Institute, 1999
Asthma in Utah Previous Study Data: • Hospitalization due to asthma • 12.3 asthma cases per 10,000 children ages 0-14 for 1992-1995 (LeFevre, 1997) • Childhood asthma hospitalization rates at the zip code level • Analysis conducted in four Urban counties
Asthma Incidence Rates by Zip Code (1992-1995) Ages 0-14 The Great Salt Lake Salt Lake County N Significantly Lower Not Significantly Different Significantly Higher Freeways W E S
Asthma in Utah In Western Salt Lake County: Increased Rate Of Childhood Asthma Many Industrial Emission Sites Relationship?
Study Objectives • Analyze the spatial and temporal variation of childhood asthma within four urban Utah counties • Determine if there is a relationship between childhood asthma development and proximity to industrial emission sources
Study Population • Study Location • Four urban Utah counties • Approx. 77% Utah’s population Salt Lake City • Asthma Cases • ICD-9 code 493 • 1990-1999 • Ages 0-14
Childhood Asthma Study Area Great Salt Lake Weber County Davis County Salt Lake City Salt Lake County Utah Lake Counties Major Roads Major Lakes Utah County
Data Collection: Asthma Cases Hospital Discharge Data: • 11,522 Cases • Name • Birth Date • Sex • Date of Admit/Discharge • Address at time of hospitalization
Data Collection: Asthma Cases Birth Certificate Data: • 8,932 Unique individuals • Race • Tobacco Use (Mother) • Alcohol Use (Mother) • Congenital Anomalies • Birth Address
Data Collection: Emission Sites Sources of Hazardous Emissions: • NPL • CERCLIS • RCRA • TRI • Point Source Emissions
Industrial Emission Sites (1990-1999) Great Salt Lake NPL TRI CERCLIS PSE RCRA X Utah Lake
Data Collection:Confounders • Socioeconomic Data • 1990 and 2000 Census Data • Access to Healthcare • Proximity to hospital • Climatological Data • Wind speed & direction, temp, humidity
Data Analysis: Statistical Tests • Cluster Identification through Spatial and Temporal Analysis • Are cases close together in space and time? • Statistical Tests Used • Knox Test • Moran’s I • Gedis-Ord G • Geary’s C
Data Analysis: Statistical Tests cont. • Relationship between emission sources and asthma cases • Lawson test • Point-specific analysis • Rule out potential confounding factors (i.e. socioeconomic & climatological data)
Status of Study • At this point: • 11,522 cases mapped based on address at time of hospitalization • 8,032 cases mapped based on birth address • 6,094 industrial emission sites identified and mapped
Conclusions • Previous study indicates increased incidence of asthma in certain areas • Ongoing analysis to identify clusters and evaluate relationship to emission sources • Final Results available Fall 2002
Questions? Contact Information: Michelle Gillette, M.P.H. Office of Epidemiology Utah Department of Health (801) 538-6191 mgillett@doh.state.ut.us Funding for this study provided by: The Agency for Toxic Substances and Disease Registry Cooperative Agreement #U50/ATU887580-03 Additional assistance provided by Dr. R. Wayne Ball, Greg Williams, Amy Coombs, Samuel LeFevre, and the University of Utah Digit Lab
References National Heart, Lung, and Blood Institute, National Institutes of Health, Centers for Disease Control and Prevention. (1999). NHLBI Data Fact Sheet: Asthma Statistics, January 1999. http://www.nhlbi.nih.gov/health/prof/lung/asthma/asthstat.htm LeFevre, S., and Ball, R.W. (1997). Health Assessment: Asthma Hospitalization Rates Among Children in Utah.