Indicator PI.8.a Proportion of population within 1/2 mile of a supermarket

PI.8.a Proportion of population within 1/2 mile of a supermarket

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Data Source

This dataset was purchased from ESRI (Redlands, CA), a private vendor, in Spring 2009. It included all businesses for San Francisco. From this dataset, the specific food retailers were selected for inclusion of this indicator. InfoUSA collects information on approximately 12 million private and public US companies. Individual businesses are located by address geocoding—not all will have an exact location. The ESRI geocoder integrates an address-based approach with more than forty million residential and commercial U.S. address records from the Tele Atlas Address Points database.

Map prepared by City and County of San Francisco, Department of Public Health, Environmental Health Section using ArcGIS software.

Table data is presented by planning neighborhood. While planning neighborhoods are larger geographic areas than census tracts, census tracts do not always lie completely within a planning neighborhood. SFDPH used ArcGIS software and a 'centroids within' methodology to convert census blocks to geographic mean center points. We then assigned census blocks to planning neighborhoods based on the spatial location of those geographic mean center points and calculated the planning neighborhood totals for the table.

Detailed information regarding geographic units of analysis, their definitions, and their boundaries can be found in the HDMT at the following links:

http://www.thehdmt.org/etc/Geographic_Units_of_Analysis.pdf

http://www.thehdmt.org/data_map_methods.php

Explanation and Limitations

Supermarkets were identified based on a modification of the Food Marketing Institute definition of a supermarket as a business that sells a variety of food and that earns annual revenues of $2 million or more each year. To include smaller markets that sometimes play an important role in urban communities, the selection criterion was defined as businesses with annual revenue greater than or equal to $1 million or that were members of a chain (either a national chain such as Safeway, Albertsons, Trader Joe’s, or a regional chain) or with the word “supermarket” in the business name. NAICS codes included 44511001, 44511002, 44511003, 44511004, 44511005.

Why is this a Community Health Indicator?

Local food environments influence the options households and individuals have. Access to healthy food choices is directly correlated to obesity and diabetes rates, which occur in higher rates among people living in low-income communities with worse food environments.a

Supermarkets may provide access to a greater variety of cheaper and healthier foods, including fresh fruits and vegetables. This access helps to facilitate healthier dietary choices. Research has found that the presence of a supermarket in a neighborhood predicts higher fruit and vegetable consumption and a reduced prevalence of overweight and obesity.b,c  As a result, problems of under- and over-nutrition are often attributed to lack of access to supermarkets.de  Low-income, minority communities typically have fewer supermarkets and grocery stores than higher SES neighborhoods with primarily White residents, and they therefore disproportionately suffer from problems of over- and under-nutrition.fgh

  1. Regents of the University of California, PolicyLink, and the California Center for Public Health Advocacy. Designed for Disease: The Link Between Local Food Environments and Obesity and Diabetes. April 2008. http://www.policylink.org/documents/DesignedforDisease.pdf.
  2. Morland K, Diez Roux AV, Wing S. Supermarkets, other food stores, and obesity: the atherosclerosis risk in communities study. Am J Prev Med. 2006;30(4):333-9.
  3. Inagami S, Cohen DA, Finch BK, Asch SM. You are where you shop: grocery store locations, weight, and neighborhoods. Am J Prev Med. 2006;31(1):10-7.

  4. Short A, Guthman J, Raskin S.  Food Deserts, Oases, or Mirages? Small Markets and Community Food Security in the San Francisco Bay Area.  Journal of Planning Education and Research 2007; 26: 352-364. 

  5. Zenk SN, Schulz AJ, Hollis-Neely, T, Campbell RT, Holmes N, Watkins G et al.  Fruit and Vegetable Intake in African Americans: Income and Store Characteristics.  American Journal of Preventative Medicine 2005; 29: 1-9.

  6. Zenk SN, Schulz AJ, Israel BA, James SA, Bao S, Wilson ML. Fruit and vegetable access differs by community racial composition and socioeconomic position in Detroit, Michigan. Ethnicity and Disease 2006; 16: 275-80.

  7. Morland K, Wing S, Diez Roux A, Poole C. Neighborhood characteristics associated with the location of food stores and food service places. American Journal of Preventative Medicine 2002; 22; 23-9.

  8. Morland K, Filomena S. Disparities in the availability of fruits and vegetables between racially segregated urban neighbourhoods. Public Health Nutrition 2007; 10: 1481-89.