title: Sparse modeling of spatial environmental variables associated with asthma.
abstract: Geographically distributed environmental factors influence the burden of diseases such as asthma. Our objective was to identify sparse environmental variables associated with asthma diagnosis gathered from a large electronic health record (EHR) dataset while controlling for spatial variation. An EHR dataset from the University of Wisconsin's Family Medicine, Internal Medicine and Pediatrics Departments was obtained for 199,220 patients aged 5-50years over a three-year period. Each patient's home address was geocoded to one of 3456 geographic census block groups. Over one thousand block group variables were obtained from a commercial database. We developed a Sparse Spatial Environmental Analysis (SASEA). Using this method, the environmental variables were first dimensionally reduced with sparse principal component analysis. Logistic thin plate regression spline modeling was then used to identify block group variables associated with asthma from sparse principal components. The addresses of patients from the EHR dataset were distributed throughout the majority of Wisconsin's geography. Logistic thin plate regression spline modeling captured spatial variation of asthma. Four sparse principal components identified via model selection consisted of food at home, dog ownership, household size, and disposable income variables. In rural areas, dog ownership and renter occupied housing units from significant sparse principal components were associated with asthma. Our main contribution is the incorporation of sparsity in spatial modeling. SASEA sequentially added sparse principal components to Logistic thin plate regression spline modeling. This method allowed association of geographically distributed environmental factors with asthma using EHR and environmental datasets. SASEA can be applied to other diseases with environmental risk factors.
authors.affiliation: Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin, 5795 Medical Sciences Center, 1300 University Ave, Madison, WI 53706, USA. Electronic address: tschang3@uwalumni.com.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Chang
authors.affiliation: Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin, 603 Warf Office Building, 610 Walnut St, Madison, WI 53706, USA. Electronic address: ronald@biostat.wisc.edu.
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Gangnon
authors.affiliation: Department of Biostatistics and Medical Informatics, School of Medicine and Public Health, University of Wisconsin, 6743 Medical Sciences Center, 1300 University Ave, Madison, WI 53706, USA. Electronic address: page@biostat.wisc.edu.
authors.forename: C
authors.initials: C
authors.lastname: David Page
authors.affiliation: Applied Population Laboratory, Department of Rural Sociology, University of Wisconsin, 308b Agricultural Hall, 1450 Linden Dr, Madison, WI 53706, USA. Electronic address: wrbuckin@wisc.edu.
authors.forename: William R
authors.initials: WR
authors.lastname: Buckingham
authors.affiliation: Department of Family Medicine, School of Medicine and Public Health, University of Wisconsin, 1100 Delaplaine Ct, Madison, WI 53715, USA. Electronic address: aman.tandias@fammed.wisc.edu.
authors.forename: Aman
authors.initials: A
authors.lastname: Tandias
authors.affiliation: Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706, USA. Electronic address: kelly.cowan@vtmednet.org.
authors.forename: Kelly J
authors.initials: KJ
authors.lastname: Cowan
authors.affiliation: Division of Public Health, Bureau of Environmental and Occupational Health, Wisconsin Department of Health Services, Room 150, 1 West Wilson Street, Madison, WI 53703, USA. Electronic address: carrie.tomasallo@dhs.wisconsin.gov.
authors.forename: Carrie D
authors.initials: CD
authors.lastname: Tomasallo
authors.affiliation: Department of Family Medicine, School of Medicine and Public Health, University of Wisconsin, 1100 Delaplaine Ct, Madison, WI 53715, USA. Electronic address: brian.arndt@fammed.wisc.edu.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Arndt
authors.affiliation: Department of Family Medicine, School of Medicine and Public Health, University of Wisconsin, 1100 Delaplaine Ct, Madison, WI 53715, USA. Electronic address: larry.hanrahan@fammed.wisc.edu.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Hanrahan
authors.affiliation: Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706, USA. Electronic address: theresa.guilbert@cchmc.org.
authors.forename: Theresa W
authors.initials: TW
authors.lastname: Guilbert
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000818:Animals; D001249:Asthma / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D004285:Dogs; D057286:Electronic Health Records; D004777:Environment; D005260:Female; D040362:Geographic Information Systems; D005843:Geography; D006798:Housing; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D025341:Principal Component Analysis; D012044:Regression Analysis; D012307:Risk Factors; D014922:Wisconsin; D055815:Young Adult
keywords: Asthma; Electronic health record; Environmental variables; Sparsity; Spatial statistics