Melissa J. Slotnick, MPH, MESc¹, Jaymie Meliker, MS¹, Gillian Avruskin, MS², Andrew Kaufmann, MS², Geoffrey Jacquez, PhD², and Jerome Nriagu, PhD¹. (1) Environmental Health Sciences, University of Michigan School of Public Health, 109 S. Observatory, SPHI, Ann Arbor, MI 48109, 734-647-5432, slotnick@umich.edu, (2) Biomedware, Inc., 516 North State Street, Ann Arbor, MI 48104

Investigation of the relationship between environmental contaminants and disease often involves retrospective assessment of chronic low-level exposures. Current methods for assessing these exposures are prone to misclassification due to inaccurate recall or use of single exposure measurements. Inclusion of spatial data through the use of Geographic Information Systems (GIS) is enhancing exposure assessment in environmental epidemiology; however, these tools inadequately characterize temporal changes in exposures. A Space-Time Information System (STIS) is being developed to incorporate both temporal and spatial data into exposure assessments. This software features the ability to visualize attribute changes on a continuous time scale, and to capture important characteristics of exposure that are lost with traditional GIS. Application of a STIS for reconstructing arsenic exposure in a population-based bladder cancer case-control study will be presented. Cases, recruited from the Michigan State Cancer Registry, and controls, selected by random-digit dialing, are asked to complete a telephone interview and written questionnaire to assess water consumption patterns and residential history. A STIS facilitates inclusion of spatial data, such as residence location and arsenic concentration maps, and temporal information, such as residence mobility and changes in drinking water arsenic concentration over time, to improve exposure assessment. Sensitive time-windows of exposure and potential disease clusters at different points in time will be presented, thereby illustrating the potential of a STIS to reveal associations that may fail to be detected with traditional GIS. Demonstration of this valuable tool provides insight into improving exposure assessment methodologies for numerous applications in environmental epidemiology.

Learning Objectives:

• This presentation will demonstrate application of a Space-Time Information System (STIS) to enhance exposure assessment for environmental epidemiology. A STIS moves beyond inclusion of spatial data used in Geographical Information Systems (GIS) to incorporate temporal data, such as participant mobility and sensitive time-windows of exposure, in exposure assessment. Participants will be able to visualize both spatial and temporal changes in arsenic exposure for selected study participants, and to recognize broader applications of this new technology to exposure reconstruction in epidemiological studies.

Keywords: Environmental Health, Geographic Information Systems

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.