Diabetes is a diet-sensitive chronic disease with crippling complications and costs.1 In concert with other factors, the food retail options available in the residential neighborhood may support or hinder diabetes self-management efforts and influence disease outcomes. Consequently, geographic variation in the availability of specific food vendors may contribute to disparities in diabetes self-care between affluent and deprived neighborhoods.2–4 In recent years, numerous states and localities in the United States have developed financing programs to increase the availability of supermarkets and other fresh food vendors in underserved neighborhoods. However, the health consequence of increasing physical proximity to supermarkets is still unknown. Moreover, no analyses have investigated whether geographic variation in food vendor availability plays a role in explaining neighborhood health disparities. This overarching goal of my dissertation research is to address these gaps in the evidence base.
This dissertation is broken out into three separate sets of analyses that are presented in five chapters. Chapter 1 provides an overview of the research and policy context that motivates this research. In Chapter 2, I investigate whether the association between neighborhood deprivation (NDI) and BMI is mediated by the availability of “healthful” and “unhealthful” food vendors, as is commonly assumed. In Chapter 3, I examine whether increasing supermarket proximity is associated with weight reduction among a subsample of patients living in close proximity to twelve new supermarkets. In Chapter 4, I examine the association between changes in neighborhood supermarket presence (supermarket development and closure) and changes in glycemic control (hemoglobin A1c). Finally, in Chapter 5, I summarize study conclusions and recommendations for future research.
Study subjects for each analysis represent different subsamples of adults from the Kaiser Permanente of Northern California (KPNC) Diabetes Registry, a large (>300,000 members) and well-characterized longitudinal cohort of insurance plan members with diabetes mellitus identified from clinical records and survey self-report. The Registry was an ideal data resource for research on the association between food retail change and change in clinical outcomes because all available electronic medical records (including inpatient, outpatient, laboratory and pharmacy records) could be linked with geospatial measures by the member’s address of residence.
These analyses will help further our understanding of how neighborhood deprivation “gets under the skin” and will help clarify the role of neighborhood food vendor availability in shaping clinical outcomes. The findings are directly applicable to current policy discussions on the health impacts of supermarket development in food deserts and may help policymakers evaluate policy options for improving diabetes outcomes.