Research Study: Body Weight, Diabetes and Access to Nutritious Food for Safety Net Patients

Mapping Breakdown

Described & Mapped By: Phylicia Morgan

What is ArcGIS?- It’s a geographic information system (GIS)

used for working with maps to manage and analyze geographic information

- This computer technology is ideal for creating, manipulating and displaying maps for surveillance, research and program planning

- Depending on your research objective ArcGIS can be used the link patient data to county level data such as poverty status, employment, crime areas, housing, immigration etc.

Before Mapping… Started off with the Highland Hospital Patient Data

Excel Spreadsheet In this study there were 94,159 patient entries along

with their associated variables (Addresses, Age, Gender, BMI/Weight, Ethnicity, Religion, Diabetic Status, etc.)

The spreadsheet was then uploaded into the ArcGIS software

Mapping Patient Data

Once uploaded, patient addresses were geocoded -the process of converting addresses to geographical coordinates- and then linked to the 361 Alameda County census tracts

- All counties are statistically divided into territorial units called Census Tracts

- Census tracts are used to depict county characteristics such as employment and poverty status, living conditions, educational attainment, and other variables

Highland Hospital Patients Diagnosed with Diabetes in Alameda County

Displayed above: Outlined county census tracts, the location of Highland Hospital, and the Patients Diagnosed with Diabetes

United States Department of Agriculture (USDA) Food Deserts

Food Deserts in Alameda County

According to the United States Department of Agriculture (USDA) Food Deserts are described as a: Low-income census tracts where at least 33% of the tracts population

or a minimum of 500 people in the tract must have low access to a supermarket or large grocery store A Low-income census tract is defined as having a poverty rate of

at least 20%; or the median family income for the tract does not exceed 80% of statewide median family income

Low access is defined as living more than one mile from the supermarket or a large grocery store in urban areas or more than 10 miles from the supermarket or a grocery store in rural areas

The following maps display USDA food deserts located in Alameda County, CA and their relation to Highland Hospital Patients Diagnosed with Diabetes

Food Deserts in Alameda County

As seen above, according to the definition provided by the USDA, Alameda County has six census tracts identified as food deserts; located in three main cities Hayward, Oakland and Alameda. Note that Highland Hospital is located in an identified food desert.

Patients with Diabetes and Food Deserts in Alameda County

This map shows Patients Diagnosed with Diabetes in relation to the identified county Food Deserts. Many patients lived in the food deserts located in Hayward, whereas very few patients resided in the food deserts found in Alameda.

Body Mass Index (BMI)

Body Mass Index (BMI) Status in Alameda County

Body Mass Index (BMI) is a person's weight in kilograms (kg) divided by his or her height in meters squared. Having a high BMI is known to correlate with adverse health outcomes

This study calculated the mean BMIs of the Highland Hospital Patients for each census tract and categorized the results

BMI ranges were separated into four weight status categories: Underweight: Below 18.5 Normal or Healthy Weight: 18.5 – 24.9 Overweight: 25.0 – 29.9 Obese: 30.0 and Above

The following maps display county Food Deserts and Patients Diagnosed with Diabetes among Average Patient BMIs

Average BMI of Patients in Alameda County

This map displays the Average Patient BMI for each census track in Alameda County.

Average BMI of Patients and Food Deserts in Alameda County

Above depicts the Average BMI in relation to previously identified Food Deserts in Alameda County

Average BMI and Patients with Diabetes in Alameda County

This map shows the Average BMI per census tract and the relationship with Patients Diagnosed with Diabetes in Alameda County.

Modified Retail Food Environment Index (mRFEI)

Modified Retail Food Environment Index (mRFEI) in Alameda County

The Modified Retail Food Environment Index (mRFEI) is an indicator used to measure the number of healthy and less healthy food retailers (i.e. Supermarkets, Grocery Stores, Fast Food restaurants, Convenience stores) in each census tract

Census tracts with low scores mean there are many convenience stores and fast food restaurants in the area. A score of zero indicates that there are no healthy food retailers.

The mRFEI is calculated for each census tract by using the following equation:

These maps display the mRFEI at the census level and Highland Hospital Patients diagnosed with Diabetes in Alameda County

Modified Retail Food Environment Index (mRFEI) in Alameda County

Displayed Above: Modified Retail Food Environment Index (mRFEI) at the census tract level in Alameda County

Modified Retail Food Environment Index (mRFEI) and Patients with Diabetes in Alameda County

This map illustrates the mRFEI in Alameda County in relation to Patients Diagnosed with Diabetes

Modified Retail Food Environment Index (mRFEI) and Food Deserts in Alameda County

Above depicts the mRFEI and Food Deserts in Alameda County

How Can Maps Like These Be Useful?

Identify target areas of interest or concern Monitor health progression or regression in

geographic areas by mapping the prevalence of diseases

Helps improve healthcare services in designated regions

Creates visualized data for medical research, academic and hospital organizations

THANK YOU TO ALL INVOLVED!

Resources and References

http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html

ftp://ftp.cdc.gov/pub/Publications/dnpao/census-tract-level-state-maps-mrfei_TAG508.pdf

http://downloads.esri.com/support/documentation/ao_/698What_is_ArcGIS.pdf

http://www.ers.usda.gov/dataFiles/Food_Access_Research_Atlas/Download_the_Data/Archived_Version/archived_documentation.pdf