Use of a new availability index to evaluate the effect of WIC policy changes on the food environment in New Orleans

INTRODUCTION: Existing tools to measure the food environment are labor-intensive, requiring substantial training to ensure accuracy. We developed a simple-to-use WIC Availability Index to evaluate the influence of WIC food package changes on the retail food environment. METHODS: Enumerators observed the availability of WIC foods using an instrument based on new vendor requirements for the Louisiana WIC Program. Baseline measures in WIC and (N=51) and non-WIC (N=88) stores were taken in 2009, before implementation of food package changes. An index was created to reflect availability of 10 categories of WIC foods: cereals/grains, milk/cheese, eggs, peanut butter/peas/beans, fish, juices/fruits, vegetables, infant formula, infant cereal, and infant fruits/vegetables. Each category was scored 1-10, based on the number of varieties available in relation to state requirements, resulting in an overall score of 100. Analysis of variance was conducted to compare WIC and non-WIC supermarkets, medium- and small-sized stores. RESULTS: Supermarkets had the highest index scores, followed by medium, and then small stores, with mean scores ranging from 91.9 for WIC supermarkets to 38.8 for non-WIC small stores. WIC small stores had significantly higher scores than non-WIC small stores (67.3 versus 38.8, p < 0.01). DISCUSSION: This simple-to-use tool demonstrated effectiveness in capturing differences in food availability and can be used to monitor compliance of WIC stores to the new food package requirements. Follow-up observations in the same stores studied in 2009 have just been completed, which will allow for evaluation of how these requirements influenced the overall retail environment.