Using Geographic Information Systems for Exposure Assessment in Environmental Epidemiology Studies

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.

Quantifying human exposure to air pollution—Moving from static monitoring to spatio-temporally resolved personal exposure assessment

“…This means personal exposure is a function of concentration and time (Nuckols et al, 2004). As a consequence, individuals can be exposed in any environment to a large variety of pollutants and pollutant mixes (Branis, 2010;Goldberg, 2007).…”

On ecological fallacy, assessment errors stemming from misguided variable selection, and the effect of aggregation on the outcome of epidemiological study

“…The rationale for this conclusion is as follows: Since large geographic areas for which composite data are used tend to exhibit considerable intra-regional variations in the local levels of air pollutants, individual exposure levels cannot presumably be inferred from aggregated data, and the outcome is insensitive exposure estimates (Rothman, 1986(Rothman, , 1993Elliott et al, 1992;Greenland, 2001;Gotway and Young, 2002;Elliott and Wartenberg, 2004;Nuckols et al, 2004).…”

“…In addition, even when individual-level health data are accessible, there is a difficulty to match them with socio-economic variables which are usually aggregated into census-designated statistical areas (i.e., census blocks and tracts), and are rarely available at the individual level (Elliott et al, 1992;Elliott and Wartenberg, 2004;Nuckols et al, 2004). Although geographic information systems (GIS) technology, which has spread widely in recent years (Gotway and Young, 2002;Brauer et al, 2003;Cockings et al, 2004;Elliott and Wartenberg, 2004;Nuckols et al, 2004;Scoggins et al, 2004), may simplify the establishment of such data linkages and thus help to verify the correspondence between results obtained from individual data and those obtained from areal aggregates, such comparative studies are yet largely forthcoming.…”

Estimativa de áreas de risco para hepatite A

“…O Sistema de Informação Geográfica (SIG) é a ferramenta central em estudos que avaliam a distribuição geográfica de uma doença. O SIG proporciona uma ampla variedade de procedimentos e métodos para coleta, armazenamento, visualização e análise de dados espaciais 15,16 .…”