Date of Award

2010

Document Type

Campus Access Dissertation

Department

Epidemiology and Biostatistics

Sub-Department

Epidemiology

First Advisor

Angela D. Liese

Abstract

Food availability at the neighborhood level has been increasingly recognized to influence dietary intake and risk of obesity. To date, environments supporting healthy dietary choices (e.g., supermarkets) and unhealthy choices (e.g., fast food outlets) have been mostly examined separately. The objective of our study was to evaluate the associations of both supermarkets and fast food outlets accessibility and availability with dietary intake and adiposity, among youth with diabetes (2001-2006) in the State of South Carolina, a high risk population with poor diet and health outcomes compared to normal youth. Furthermore, we explored the availability of supermarkets and fast food outlets in relation to neighborhood characteristics and also explored the spatial co-occurrence of these two outlet types. We obtained the individual-level information on youth with diabetes from SEARCH for Diabetes in Youth study. Supermarkets and fast food outlets accessibility and availability measures around the youth's residence were constructed using the food outlet data obtained from the South Carolina Department of Health and Environmental Control and InfoUSA Inc. We then examined the associations of accessibility and availability measures with overall dietary intake (represented by Dietary Approaches to Stop Hypertension, DASH adherence score) and adiposity (BMI z-score and waist circumference). Results indicated that the increased accessibility and/or availability of supermarkets was significantly associated with better dietary intake (higher DASH adherence score) and lower BMI z-score and waist circumference, among youth with diabetes, even after adjusting for individual-level and neighborhood-level risk factors. These associations further strengthened when controlling for fast food outlets accessibility or availability. In contrast, the associations of fast food outlets accessibility and availability with overall dietary intake and adiposity were in an unexpected direction and mostly non-significant. Exploration of the availability of supermarkets and fast food outlets by neighborhood characteristics showed that areas with supermarkets and/ or fast food outlets had a higher socio-economic status and low proportion of minority population. Furthermore, almost 75% of the supermarkets had at least one fast food outlets within 0.3 mile, thus demonstrating the spatial co-occurrence of both outlets. The findings from this study thus suggest that increased accessibility and availability of supermarkets around the residence may be significantly associated with better dietary intake and ultimately reduced adiposity in our population of youth with diabetes. The associations of fast food outlet commonly considered as environment supporting unhealthy dietary choices such as energy-dense unhealthy food, with overall dietary intake and adiposity, however, remains inconclusive. Future studies should explore both home and school fast food environment that may similarly influence the eating behavior and hence the health outcome. Further, the findings from this study regarding the spatial co-occurrence of environment supporting healthy and unhealthy dietary choices suggests that future studies exploring the associations of food environment with diet or diet-related health outcome should concurrently examine all aspects of food environment (healthy and unhealthy) in order to disentangle the various contextual drivers of dietary intake and health outcomes.

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