The dynamics and impacts of retail supermarket decentralization in Detroit, Michigan.

摘要

This dissertation integrates a social ecological framework with GIS, historical records, survey data and multivariate statistics to examine the transformation of the tri-County Detroit, Michigan food environment from 1970 to 2010. It documents how patterns of retail supermarket decentralization combined with a racially selective residential suburbanization process to create an uneven food environment characterized by a city-suburb dichotomy in which the predominately African American city of Detroit was devoid of national and regional supermarkets and the predominately-White suburbs were awash in stores. It shows how these disparities were further exacerbated by a massive economic restructuring among the major national and regional supermarkets operating within the tri-County, Detroit region. Last, it examines how disadvantaged residents responded to these changing conditions and how limited food environments shape public health outcomes as measured by dietary-intake levels. In so doing, this dissertation challenges several assumptions and fills in some missing gaps within the existing "food desert" literature.;First, it tests the prevalent assumption within the "food desert" discourse that socially and economically marginalized residents living in a limited food environment disproportionately rely on the convenience, corner grocery and liquor stores nearest to them for their food provisions. This dissertation finds that socially and economically marginalized residents---regardless of economical and physical mobility constraints---overwhelming shop outside their immediate food environment at independent, discount and national and regional full-service supermarkets in the city of Detroit and its suburbs. Consequently, this research shows that direct effects of the immediate food environment in explaining differentials in dietary-intake levels is assuaged by such shopping patterns. Sociodemographic factors play a greater role in explaining differentials in dietary-intake levels while the local food environment plays an indirect role by imposing additional travel burdens upon an already marginalized population.;Second, this dissertation elucidates how rates of retail supermarket accessibility have changed in relation to levels of neighborhood economic deprivation and neighborhood racial composition. It shows that there were initially very few differences with respect to store composition and accessibility levels across the tri-County Detroit region in 1970. However, by 1980 racial and economic disparities in store composition and accessibility levels emerged. Low-income White census tracts began to have more national and regional supermarkets than comparable low-income African American tracts. Moreover, racial composition became a major force in explaining the presence of a national and regional supermarket across tri-County Detroit by 1990. The emergence of race also reflected a polarized landscape in which impoverished African American census tracts had fewer national and regional supermarkets and a greater number of corner grocery and liquor stores than affluent White census tracts.;Last, it tests the methodological assumption that neighborhood processes related to the food environment can be captured accurately by arbitrary administrative boundaries such as a census tract. Utilizing spatial clustering algorithms to generate new neighborhood configurations across the study area, this dissertation shows that the spatial inequities in the tri-County Detroit food environment and the processes of racial and economic stratification driving them are not an artifact of census geography. Extreme disparities between low-income African American neighborhoods and wealthy White neighborhoods persist.