Communities of excellence in nutrition, physical activity, and obesity prevention (CX3) project uses GIS mapping of low-income neighborhood food environments

Growing evidence shows the connection between the retail food environment and rates of obesity, overweight and other health conditions. Documenting conditions such as access to supermarkets and proximity of fast food to schools in low-income neighborhoods to accurately convey the food environment is an important strategy for stimulating community action and policies. Since 2006, over 80 low-income neighborhoods in California have been assessed by 23 health departments through Communities of Excellence in Nutrition, Physical Activity and Obesity Prevention (CX3). Developed by the Network for a Healthy California, California Department of Public Health, CX3 is an evidence-based, program planning and policy promotion framework. Standardized tools and methods have been developed for measuring indicators in the neighborhood food environment using a combination of GIS mapping and field surveys. Each site chooses 3-7 low income neighborhoods defined by census tracts. The GIS-based methods are used to gather an initial look at community food environments which can inform decision making and survey work. GIS data show an estimated 57% of low-income neighborhood populations are not served by a grocery store within a ½ mile for residents, 31% of neighborhoods have a farmers' market, 82% within 5 miles, with 63% of markets within 5 miles having convenient public transit. A saturation of fast food in neighborhoods is evident with a worst case scenario of 28 restaurants in one census tract. An average ratio of fast food outlets to the population was 1 for 1064 people and neighborhood schools have an average of 6 fast food outlets within ½ mile.