Background Studies of the built environment and physical activity have implicitly assumed that a substantial amount of activity occurs near home, but in fact the location is unknown. Purpose Examine associations between built environment variables within home and work buffers and moderate-vigorous physical activity occurring within these locations. Methods Adults (n= 148) from Massachusetts wore an accelerometer and GPS unit for up to four days. Moderate and vigorous intensity activity was quantified within 50 m and 1 km home and work buffers. Multiple regression models were used to examine associations between five objective built environment variables within 1 km home and work buffers (intersection density, land use mix, population and housing unit density, vegetation index) and moderate-vigorous physical activity within those areas. Results The mean daily minutes of moderate-vigorous physical activity accumulated in all locations = 61.1 ± 32.8, while duration within 1 km home buffers = 14.0 ± 16.4 min. Intersection density, land use mix, and population and housing unit density within 1 km home buffers were positively associated with moderate-vigorous physical activity in the buffer, while a vegetation index showed an inverse relationship (all p< 0.05). None of these variables showed associations with total moderate-vigorous activity. Within 1 km of work, only population and housing unit density were significantly associated with moderate-vigorous physical activity within the buffer. Conclusions Findings are consistent with studies showing that certain attributes of the built environment around homes are positively related to physical activity, but in this case only when the outcome was “location-based”. Simultaneous accelerometer-GPS monitoring shows promise as a method to improve understanding of how the built environment influences physical activity behaviors by allowing activity to be quantified in a range of physical contexts and thereby provide a more explicit link between physical activity outcomes and built environment exposures.

Because residential proximity to tobacco outlets influences smoking cessation, zoning restrictions to limit tobacco sales in residential areas may complement existing efforts to reduce tobacco use.

Geographic information systems (GIS) and related technologies like remote sensing are increasingly used to analyze the geography of disease, specifically the relationships between pathological factors (causative agents, vectors and hosts, people) and their geographical environments. GIS applications in the United States have described the sources and geographical distributions of disease agents, identified regions in time and space where people may be exposed to environmental and biological agents, and mapped and analyzed spatial and temporal patterns in health outcomes. Although GIS show great promise in the study of disease, their full potential will not be realized until environmental and disease surveillance systems are developed that distribute data on the geography of environmental conditions, disease agents, and health outcomes over time based on user-defined queries for user-selected geographical areas. OVERVIEWThe geography of disease, an important component of medical geography, comprises the spatial analysis of pathological factors (causative agents, vectors, hosts, reservoirs, and people) and their relationships to geographical environments (physical, cultural, and biological) (35,46). The medical geographic approach to the study of disease has not been the dominant perspective in the United States. Nevertheless, efforts to map the spatial distribution of human cases of disease and the geography of environmental risk at local, regional, and even global scales have been made again and again throughout our history (45,47,62,66). The development of geographic information systems (GIS), computer-based systems for integrating and analyzing spatially referenced data, has provided new tools for medical geographic research on disease. GIS and related technologies such as remote sensing are enabling technologies (22,38), applicable in many academic disciplines and professions and adopted in some of these well before the earliest applications in public health. Recent books describing public health applications of GIS in the United States (21, 48) and the other contributions on GIS published in this volume suggest that the diffusion of GIS into health research and public health practice has moved beyond the early innovation phase.

This pilot study provides evidence that the addition of GPS to accelerometer monitoring improves physical activity mode classification to a small degree. Larger studies among free-living individuals and with an expanded range of activities are needed to replicate the current findings and further determine the merits of using GPS with accelerometers for mode identification.

Objectives To assess the relative accuracy and usefulness of web tools in evaluating and measuring street-scale built environment characteristics. Methods A well-known audit tool was used to evaluate 84 street segments at the urban edge of metropolitan Boston, Massachusetts, using on-site visits and three web-based tools. The assessments were compared to evaluate their relative accuracy and usefulness. Results Web-based audits, based-on Google Maps, Google Street View, and MS Visual Oblique, tend to strongly agree with on-site audits on land-use and transportation characteristics (e.g., types of buildings, commercial destinations, and streets). However, the two approaches to conducting audits (web versus on-site) tend to agree only weakly on fine-grain, temporal, and qualitative environmental elements. Among the web tools used, auditors rated MS Visual Oblique as the most valuable. Yet Street View tends to be rated as the most useful in measuring fine-grain features, such as levelness and condition of sidewalks. Conclusion While web-based tools do not offer a perfect substitute for on-site audits, they allow for preliminary audits to be performed accurately from remote locations, potentially saving time and cost and increasing the effectiveness of subsequent on-site visits.