High-density poultry operations and community-acquired pneumonia in Pennsylvania

Background: Air pollution from industrial food animal production may increase vulnerability to pneumonia among individuals living in nearby communities. We evaluated the association between individual-level residential proximity to high-density poultry operations and diagnosis with community-acquired pneumonia (CAP). Methods: We conducted a nested case-control study among patients of a large health system in Pennsylvania, USA. We used diagnostic codes for pneumonia and chest imaging from electronic health records from 2004 to 2015 to identify 11,910 child and adult cases of CAP and 59,550 frequency-matched outpatient controls. We estimated exposure to poultry operations using data from nutrient management plans, calculating an inverse-distance squared activity metric based on operation and residential addresses that incorporated number, size, and location of operations. Mixed effects logistic regression models evaluated associations between quartiles of the activity metric and CAP diagnosis. Models controlled for sex, age, race/ethnicity, Medical Assistance (proxy for low socioeconomic status), and smoking status. Results: Individuals living in the highest (versus lowest) quartile of the poultry operation metric had 66% increased odds of CAP diagnosis (adjusted odds ratio [confidence interval]) Q2, 0.98 [0.74, 1.31]; Q3, 1.17 [0.93, 1.46]; Q4, 1.66 [1.27, 2.18]). Conclusions: Findings suggest that living in closer proximity to more and larger poultry operations may increase risk of CAP, contributing to growing concern regarding public health impacts of industrial food animal production.