Using school fitness testing data and geographic information systems (GIS) to characterize childhood obesity by zip code: Riverside County, California

As local health departments struggle to confront the epidemic of childhood obesity, there is a persistent need for reliable estimates of the magnitude and distribution of the problem. While obesity prevalence data is readily available at the state and county level, finding meaningful data for individual communities within the county is far more challenging. Annual fitness testing in public schools provides a novel source for analyzing trends in childhood obesity at the local level. Each year students attending public schools across California take part in physical fitness tests that evaluate a child's performance according to established benchmarks. There are six separate tests, including the Body Composition test which is used to gauge obesity by calculating the child's Body Mass Index. Students who do not meet the standard are said to fall outside of the Healthy Fitness Zone (HFZ). For our purposes, we characterized childhood obesity by determining the percent of students, by school zip code, which fell outside of the HFZ for the Body Composition test. Data for students in grades 5, 7, and 9 at all schools located within each zip code was aggregated and the Percent Overweight, Relative Standard Error, and Confidence Intervals were calculated. The resulting maps and data products demonstrate the dramatic differences across communities in childhood obesity prevalence. The results have been used in presentations and publications, leading to local press coverage. Local policy makers, community coalitions, nutritionists, and researchers have used the data to help plan interventions and refine their outreach efforts.