Using GIS to assess the relationship between the built environment and obesity among adults in los angeles county

Areas with increased access to “bad” food outlets, such as fast-food restaurants, may be associated with higher rates of obesity. Food outlet addresses collected by the Los Angeles County (LAC) Department of Public Health in 2010 were geocoded and used to calculate the number of fast-food outlets per 100,000 population for each LAC health district (HD) (n=26). To examine the relationship between obesity and food environment, these numbers were plotted over indirect estimates of obesity (BMI>=30 kg/m2 for adults 18 years old and older) from the 2009 California Health Interview Survey using ArcGIS10.1. San Antonio, a predominantly young, Latino district with the highest obesity rate (36%), had one of the most fast-food outlets (86 outlets/100,000 population). Central, an ethnically diverse district with an average obesity rate (28%), had the most fast-food outlets overall (131 outlets/100,000 population), while West, a predominantly White district with the lowest obesity rate (11%), had an average number of fast-food outlets (81 outlets/100,000 population). Additional analyses will consider other area-level factors, such sociodemographic characteristics, another measure of fast-food density (i.e., average distances between outlets relative to each total HD area), and average park space, to further assess this geographic variation in obesity and fast-food outlets. HDs with many fast-food outlets per population tended to have high obesity rates, but the relationship varied across HDs. While no causal inference can be made using cross-sectional data, GIS analyses provide the opportunity to assess factors influencing obesogenic environments in LAC, which may guide local health policies and future research.