Spatial Patterns in Foodborne Illness in Oklahoma County Residents 2001-2010

The incidence of foodborne illness in Oklahoma County is high (47.5 per 100,000 vs 41.5 per 100,000 nationally), and the burden on the public health system, healthcare system, and population is heavy.  The Oklahoma City-County Health Department is working to reduce this burden through education, mitigation, and partnerships.  To facilitate this, a spatial analysis of reported cases from 2001-2010 was conducted.  A random case distribution was hypothesized with areas of higher incidence representing potential areas for targeted education.  Data were aggregated at the zip code level and spatial analyses performed.  Descriptive analyses were conducted along with Poisson analyses testing the hypothesis that the number of cases in a zip code was proportional to its population.  Zip codes or zip code groups with a significantly higher proportion of cases were identified as clusters.  Covariates were added for potential high risk groups.  Analyses were performed with one, five, and 10 year time aggregation.  Clusters were identified for major foodborne infections.  Descriptive analyses showed an association with living in rural or wealthy areas. Little change was observed with the addition of covariates.  Additional analyses showed most clustering occurred in the vicinity of a major hospital.  Disease reporting relies on ill individuals seeking care and adequate testing and reporting.  The clustering identified in this analysis suggests more about care-seeking and hospital/physician reporting behaviors than disease risk.  Those with convenient medical access may be more likely to seek care for foodborne illness, and the facilities they use may have increased reporting standards.  Further investigation is necessary to determine if either of these is true. Continued education for physicians around disease reporting is recommended.  Future analyses will need adjustment for the identified areas of high reporting.