Epidemiologic investigations of environment-cancer relationships rely on accurate, quantifiable exposure measurements. Such studies may use geographic information systems (GIS) and regulatory and other environmental monitoring data to complement retrospective surveys, which are sometimes limited by participants’ knowledge of exposures in their surrounding environments. Cancer studies have benefited from the increasing availability of historical air and water monitoring data, satellite imagery, census, and other geographic datasets that allow for reconstruction of residence- and other location-based exposures over a substantial portion of a person’s lifetime.
Investigators in the Occupational and Environmental Epidemiology Branch implement GIS-based exposure assessments using georeferenced historical data resources and residential histories collected in our studies of environmental hazards and cancer risk. Our approaches include using GIS and spatial-analytic methods to characterize exposure to environmental risk factors, incorporating space-time-activity information in exposure assessments, and employing biological and environmental measurements for exposure validation. This work addresses important epidemiologic considerations in geography-based environmental exposure assessments, including residential mobility, positional error, and the challenges of extrapolation over space and time.