Diabetes is an epidemic in the United States with over of 30 million people affected (American Diabetes Association, 2020). This corresponds with a prevalence of approximately 10 percent (Centers for Disease Control, 2019). Another approximately 90 million in the U.S. have prediabetes (American Diabetes Association, 2020). Globally, we have a pandemic, with an incidence close to one half billion individuals affected by diabetes (World Health Organization, 2014). Despite the staggering numbers, many people remain unaware of the diabetes pandemic (International Diabetes Federation, 2017). Unlike the infamous infectious pandemics of the past such as the plague and the flu that left victims dead on the streets, type 2 diabetes is a non-infectious silent disease that quietly takes its toll on its victims, long before even being diagnosed (American Diabetes Association, 2017). Furthemore, those with diabetes have been noted to have worse outcomes if they are diagnosed with COVID-19.
As such, there have been a number of studies conducted regarding diabetes in the Philadelphia region. Most of these studies have traditionally employed “spatial approaches” to food access. An example of a “spatial approach” (Hirsch, 2013) might read as follows: “....living 0.5 miles from the closest supermarket.” A recent study conducted in Philadelphia (Hirsch, 2013) utilized the concept of “activity spaces” and Geographic Information Systems (GIS) in an attempt to better define the environment in which individuals do their food shopping and the perception of residents’ food environments. In this study, the food purchasing decisions of residents living in “favorable food environments” as well as those residing “unfavorable food environments” were both directly tied size of the food purchase and availability of transportation (car) (Hirsch, 2013). It is for this reason that we will address transportation as an additional independent variable.
Vehicle ownership/availability as it relates to access to healthy food choices and risk for type 2 diabetesHaving access to a car affords food desert residents an opportunity for food security by temporarily escaping for healthy food shopping at a full service food market. Studies have examined whether proximity to fast food outlets can account for the higher prevalence of obesity (an established risk factor for type 2 diabetes) in low-income minority priority populations. A study conducted in Los Angeles (Inagami, 2009) examined the relationship between fast food and general restaurant access, neighborhood socioeconomic levels, BMI of (young male Latino) residents and whether this association is moderated by car ownership. The results of the study support the possibility that those people able to travel farther may have better access to healthier foods, while those without transportation are more likely to patronize convenience stores that sell energy-dense foods that contribute to obesity and diabetes (Inagami, 2009). Another study (already mentioned above) also identified lack of transportation as a physical barrier between food desert residents and access to healthy food shopping opportunities (Cuesta-Briand, 2011).The USDA Defines Food Desert as “parts of the country vapid of fresh fruit, vegetables, and other healthful whole foods, usually found in impoverished areas. This is largely due to a lack of grocery stores, farmers' markets, and healthy food providers” (American Nutrition Association , 2011). Across all communities, there is a direct correlation between the prevalence of obesity and diabetes and the ratio of fast-food restaurants and convenience stores to full service grocery stores and produce vendors where they live (Ingami, 2009). Previous studies have shown that people of lower SES residing in communities that do not offer many healthy choices have the highest rates of obesity and diabetes. Previous research has suggested that health outcomes are a product of the types of foods available in the community and the associated dietary behaviors of the residents (UCLA, 2008). Our objective is to perform a thorough review of the previous work in this area and to develop definitive conclusions based on the existing data. We will also offer suggestions on how to help alleviate the burden of food deserts in our nation. We will attempt to address recurring themes that come up in the literature such as, urban vs rural environments, travel distance to the closest full service supermarket and access to a car. Urban vs. rural environmentIt has already been established in the literature that dietary patterns predict risk for type 2 diabetes (Van Dam, 2002). When one thinks of a food desert the image that comes to mind is often an urban setting where there are large numbers of people, geographically segregated, without access to healthy food choices. While this is true, there are also rural food deserts, where extended travel distance and hardship also makes it difficult to find and purchase healthy foods at affordable prices (Miller, 2016). Car ownership, education and SES influence the distance that people in urban and rural environments are willing and able to travel in search of food (Hirsh, 2013).
Research questions The research questions of this proposal are: What is the relationship between residing in food deserts, making healthy food choices and the prevalence of type 2 diabetes Additionally, is how does lack of access to an automobile play into the situation as another independent variable or risk factor.Research hypothesisIt is hypothesized that residing in food deserts is a social disparity that limits residents’ access to healthy food choices at affordable prices, consequently increasing the risk of type 2 diabetes for this population. Additionally, it is hypothesized that lower prevalence of car ownership allows less opportunities to travel in search of healthy food choices and therefore also contributes (as an independent variable or an additional risk factor) to an increased risk of type 2 diabetes.Methods and proceduresResearch study designA cross-sectional, community-based survey study design will be employed over an 8 week period, among individuals of either sex, aged 18 years and older. The study will be carried out in neighbors of Philadelphia, PA identified as food deserts. This study was used to show the prevalence of diabetes. In this study the prevalence of diabetes is the proportion of individuals with self-reported diabetes in the population of study. This study will also be used to assess the relationship among diabetes prevalence and vehicle ownership. The independent variable (the exposure) in this study is the individuals’ residing in a neighborhood defined as a food desert. An additional independent variable (possibly a confounding variable) is automobile ownership or easy access to an automobile. The dependent variable (the outcome being measured) is the risk of acquiring type 2 diabetes. It is important to examine the role that transportation plays in escaping the food desert in search of healthier choices. Having access to a car may affect the internal validity of this study because we need to know if the results are truly attributable to the primary exposure (residing in a food desert). It is important to note that the majority of the studies we have referenced have made some type of reference as to the importance of automobile availability in acquiring healthy foods, regardless of what the primary objective of the studies may have been.The prevalence of diabetes and risk factors of diabetes will be presented as percentages. A Chi-square test for trend will be used to assess the trends in the prevalence of diabetes among vehicle ownership. A P value of < 0.05 will be considered significant. Several studies have confirmed the association of socioeconomic status with diabetes. However, there have been few studies which analyzed vehicle ownership particularly and its relation to diabetes. If people live in neighborhoods which do not have food stores with healthy food options, they can still access food stores in nearby places if they own a personal vehicle. However, in most cases, people living in low income neighborhoods such as food deserts, often do not own vehicles. Food desert residence and car ownership will be assessed using survey items.
Subject recruitment and selection
According to the United States Department of Agriculture (USDA) there are many ways to measure food store access for individuals and for neighborhoods, and many ways to define which areas are food deserts or neighborhoods that lack healthy food sources. Most measures and definitions take into account accessibility to healthy food sources measured by distance to a store or by the amount of stores in an area, individual resources that may affect accessibility, such as family income or vehicle availability, and neighborhood indicators, such as the average income of the neighborhood and the availability of public transportation. The USDA Food Access Research Atlas (FARA) maps food access indicators for census tracts using ½-mile and 1-mile demarcations to the nearest supermarket for urban areas, low income status, and vehicle availability for all tracts. The FARA allows users to view census tracts by food access indicators using these different measures. Food deserts were identified using the USDA Food Access Research Atlas (FARA). The food desert indicators of interest include the number of individuals who live more than 1 miles away from a supermarket within each census tract, the total number of individuals at low access who are also of low income, and the total number of households at low access, without access to a vehicle. Low income was defined as persons with an annual income below or equal to 200 percent of the federal poverty line. Three food deserts were identified using indicator measures. The field areas of study that were identified as food desert using FARA will include the Overbrook neighborhood in West Philadelphia, and the Fox Chase, and Normandy neighborhoods in Northeast Philadelphia. Of these locations 10 corner stores will be identified in each location. Permission will be requested from store owner via phone or in person to administer survey. Approximately 20 surveys will be administered at each study site.Survey questions were selected from the CDC’s Youth Risk Behavior System (YRBSS). The YRBSS monitors health risk behavior among youths and adults including unhealthy dietary behaviors. Survey questionnaires will be administered to a convenient sample approximately 600 customers at 30 convenience store located in food deserts neighborhoods of Philadelphia. Survey measures include customer dietary behavior, diabetic prevalence, shopping frequency, distance traveled, food accessibility, SNAP participation, and demographic information.
Inclusion and exclusion criteriaParticipation is voluntary. Survey respondents must be male or female customers of the convenience stores included in our study. An individual may participate in the survey only once. Participants must 18 years of age or older and must be willing to voluntarily and anonymously complete our questionaire. Potential confounding variables might include age, body mass index, levels of physical activity and smoking status. While excluding those people from the research study might yield more accurate results, we probably would be left with a very small pool of eligible patients.
Location of the studyThe location of the study will be at convenience stores located in low income, urban, neighbors of Philadelphia identified as food deserts environments by the researchers using FARA maps.Survey questionnaires will be administered to customers at any of the 30 corner store located in food deserts neighborhoods of Philadelphia.Participant proceduresThe population for this study would consist of individual residing in food deserts of Philadelphia. Undergraduate public health student volunteers embedded into the community will approach customer by asking them to participate in a brief survey about the nutrition behavior and environment. A 20 item survey administered to convenience store customers will either be self administered or administered by the researchers. Convenience store customers can voluntary participant in survey questionnaire. Survey will approximately take 5 minutes to complete. Respondents may stop at any time during the survey. Approximately 20 surveys will be collected from each convenience store site. Refusals of survey participation will be recorded. After completion, the survey will be collected. Survey collection will be completed in an eight week study period.Protection of subjectsConfidentiality and anonymity The Survey is voluntary and participants can stop at any time during the survey. We will not collect information that could be used to identify or contact an individual. Data will be kept in encrypted hard drives for research access only.
Potential risks or discomforts to patientsThere are minimal potential risks or discomforts anticipated to the subjects. Survey is brief and will approximately only take 5 minutes to complete. The Questionnaire is voluntary respondents discontinue participation at any time. Potential benefitsHigh fat and carbohydrate diet are considered risk factors for type 2 diabetes. Therefore, the food environment in which an individual resides may determine to a large extent whether an individual has a higher probability of developing diabetes. Most of the studies related to the built environment, food access and health outcomes have focused on mainly on obesity. There have not been a large number of studies which looked at the association between food environment, diabetes prevalence and having adequate transportation to actually arrive at the healthy food shopping destination. Accessibility and availability of supermarkets, grocery stores and fast food joints influence the health status of individuals, especially when it comes to obesity and type 2 diabetes. A healthy diet is a major key to preventing and managing type 2 diabetes. Avoiding fatty food and consuming a variety of whole grains, fresh fruits and vegetables, lean meats and limited carbohydrates can reduce the prevalence of diabetes (American Diabetes Association, Fat and Diabetes, 2013). Access to quality food can play a crucial role in determining the diabetes health status of individuals. Philadelphia is plagued with several food deserts where there is no access to grocery stores of supermarkets. Residents of these neighborhoods usually belong to the low income population. They often have to travel long distances to reach a grocery store which at times may not be possible because of a lack of vehicle ownership. Under such circumstances, individuals with a lack of access to healthy food are at higher risk for obesity, and dietary-related health problems such as diabetes. This study highlights the importance of access to healthy food and its implications on diabetes health status. It examines whether there is an association between lack of access to fresh food, large grocery stores or supermarkets in low income, USDA designated food deserts in Philadelphia, PA and the prevalence of diabetes among the residents. The study examines whether one’s geographic location within the Philadelphia influences health status measured by diabetes prevalence. It looks at factors such as household income, transportation and race/ethnicity in food deserts and determines whether there is a significant difference in diabetes prevalence based on the above factors.
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