Table 1 Definition of types of food stores used in this study

Supercenters or superstores

Very large stores that primarily engage in retailing a general line of groceries in combination with general lines of new merchandise, such as apparel, furniture, and appliances (e.g., Super Wal-Mart, Super Kmart).

Supermarkets

Primarily engage in retailing a general line of food, supermarkets are larger in size (>20,000 sq ft), number of employees, and sales volume [98]. Chain store identification and number of parking spaces (>100) were used to distinguish supermarkets from grocery stores [65, 108].

Grocery stores

Primarily engage in retailing a general line of food, grocery stores are smaller in size, not identified as a chain store and have fewer than 100 parking spaces.

Convenience stores or food marts

Primarily engage in retailing a limited line of goods that generally includes milk, bread, soda, and snacks. The convenience store category also included convenience stores with gasoline and gasoline stations with convenience stores.

Mass merchandisers

Large, general merchandise "value" stores, such as Kmart, Target, and Wal-Mart.

Dollar stores

Limited-price general merchandise "value" stores, such as Dollar General or Family Dollar [65, 93].

Pharmacies and drug stores

Pharmacies and drug stores that were part of national chains (e.g., CVS, Walgreens).