Proximity to Swine Farming Operations as a Risk Factor for Eosinophilic Esophagitis

We aimed to determine whether residential proximity to permitted swine facilities was associated with an increased risk of eosinophilic esophagitis (EoE) by conducting a case-control study using 2 complementary data sources: 1 from a tertiary care center (n = 401 cases and 1805 controls) and 1 from a large pathology group (n = 904 cases and 4074 controls). Addresses of the subjects and swine facilities were geocoded, and adjusted odds of EoE relative to proximity to and density of swine facilities were calculated. We observed a positive association between proximity to a permitted swine facility (<1 mile) and odds of EoE (adjusted odds ratio R, 2.56; 95% CI, 1.33-4.95) in the tertiary center data; density of farms (>10 farms/census tract) was also positively associated (adjusted odds ratio, 2.76; 95% CI, 1.30-5.84). However, this association was not observed in the pathology database. Though proximity to and density of swine operations were associated with EoE, associations were sensitive to the database used.