Effects of The Built Environment, Crime & Food Prices on BMI, Activity & Eating

The Moving to Opportunity for Fair Housing Demonstration (MTO) provided an excellent setting to examine the role of neighborhood characteristics on obesity, physical activity and fruit/vegetable intake. The goal of MTO was to determine whether persons who moved to "better" neighborhoods would experience improvements in a variety of outcomes such as education, economic and health compared to similar persons who did not move. To ensure that comparisons were made between similar persons, families were randomly assigned to one of three groups: the experimental group (who were required to move to census tracts where less than 10% of persons lived in poverty), the Section 8 group and the control group. The key advantage of the MTO data is participants were randomized to treatment and control groups, which would likely eliminate any baseline differences among these groups. Since many weight loss interventions fail, an important finding of the MTO study was that adult participants (N=3526) in the experimental group had a significantly lower BMI 4 to 7 years after randomization compared to controls. Additionally, those in the experimental group had a higher frequency of fruit and vegetable consumption and those in the Section 8 experimental group had a greater frequency of physical activity relative to controls. Thus the purpose of our research was to examine whether the differences in these outcomes seen across study groups were mediated by attributes of the participant's environment. This study linked MTO Interim Evaluation data with environmental characteristics of participant's neighborhoods. The MTO Interim Evaluation included information on health outcomes including BMI, physical activity levels and consumption of fruit and vegetables along with demographic information. Environmental characteristics that were collected and linked with the Interim Evaluation include: food availability, food prices, commercially and publicly available physical activity resources, city-sponsored recreation centers, connectivity of streets, land use, residential density, crime statistics and census data.

Defining The Built Environment

Most built environment research relies on prescribed geographic boundaries such as census tracts, though many researchers have noted that these boundaries are unlikely to match an individual's perception of his/her neighborhood. A definition of neighborhood boundaries that matches resident perceptions and accurate descriptions of neighborhood resource use patterns could assist with identifying the environmental factors that contribute to the development of obesity and ultimately lead to more targeted environmental interventions to decrease the prevalence of obesity. Many studies of the built environment and obesity have concentrated on urban areas, but few have examined adolescent residents of subsidized housing complexes. Ecological models of health outcomes have not guided public housing policymakers' decision-making about estate construction and placement. There are important and practical policy implications if research can demonstrate that estate location and design affect obesity prevalence. This study employed a combination of quantitative and qualitative methods to explore the effects of the self-defined built environment on the consumption and physical activity behaviors of 140 adolescent residents of public housing estates.