Measuring the Retail Food Environment in Rural and Urban North Carolina Counties

Background: Development of accurate and sensitive methods to characterize the food environment is needed. Thus, we examined convergent and criterion validity of 2 retail food environment data sources and then examined differences in predictive validity between 3 ways of measuring the rural and urban food environment. Methods: Ten counties were selected in each of 3 North Carolina regions (n = 30). Number of fast-food restaurants and chain supermarkets were calculated using 2 data sources. Convergent validity was percent agreement between the 2 sources. Criterion validity was percent agreement between each source and the most accurate venue count. Predictive validity of food environment measures (Retail Food Environment Index, fast-food restaurants/capita, and supermarkets/capita) was calculated by associations with county-level mean-weighted body mass index (BMI). Results: Percent agreement for fast-food restaurants ranged from 50% to 100% (mean = 87%) and for supermarkets ranged from 58% to 100% (mean = 89%). The 2 data sources had similar percent agreement with the most accurate count. Retail Food Environment Index was positively associated with BMI, while fast-food restaurants per capita were negatively associated with BMI. Conclusions: Our results lend support to studies using both food environment data sources examined.