| Using Geographic Information Systems for Exposure Assessment in Environmental Epidemiology Studies John R. Nuckols,1 Mary H. Ward,2 and Lars Jarup3 1Department of Environmental and Radiological Health Sciences, Colorado
State University, Fort Collins, Colorado, USA; 2Occupational and
Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics,
National Cancer Institute, National Institutes
of Health, Department of Health and Human Services, Bethesda, Maryland, USA; 3Small
Area Health Statistics Unit, Department of Epidemiology and Public Health, Imperial
College London, London, United Kingdom Abstract
Geographic information systems (GIS) are being used with increasing frequency in environmental epidemiology studies. Reported applications include locating the study population by geocoding addresses (assigning mapping coordinates) , using proximity analysis of contaminant source as a surrogate for exposure, and integrating environmental monitoring data into the analysis of the health outcomes. Although most of these studies have been ecologic in design, some have used GIS in estimating environmental levels of a contaminant at the individual level and to design exposure metrics for use in epidemiologic studies. In this article we discuss fundamentals of three scientific disciplines instrumental to using GIS in exposure assessment for epidemiologic studies: geospatial science, environmental science, and epidemiology. We also explore how a GIS can be used to accomplish several steps in the exposure assessment process. These steps include defining the study population, identifying source and potential routes of exposure, estimating environmental levels of target contaminants, and estimating personal exposures. We present and discuss examples for the first three steps. We discuss potential use of GIS and global positioning systems (GPS) in the last step. On the basis of our findings, we conclude that the use of GIS in exposure assessment for environmental epidemiology studies is not only feasible but can enhance the understanding of the association between contaminants in our environment and disease. Key words: environmental epidemiology, exposure assessment, geographic information systems. Environ Health Perspect 112:1007-1015 (2004) . doi:10.1289/ehp.6738 available via http://dx.doi.org/ [Online 15 April 2004]
This article is part of the mini-monograph "Health and Environment Information Systems for Exposure and Disease Mapping, and Risk Assessment." Address correspondence to J.R. Nuckols, 125 EHB, Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523 USA. Telephone: (970) 491-7295. Fax: (970) 491-2940. E-mail: jnuckols@colostate.edu Special acknowledgement is given to S. Weigel for her contribution to the text used in the section on geospatial sciences, and to P. Stewart (OEEB-NCI) for her input on the exposure assessment process. Preparation of this article was funded in part by an intergovernmental personnel agreement between OEEB-NCI-NIH-DHHS and Colorado State University. The authors declare they have no competing financial interests. Received 12 September 2003 ; accepted 25 March 2004.
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