Fig. 1.

Source population, including individuals with a dairy production address in the outlined 20-county region of Wisconsin (lighter shaded 20 counties) and who were: (1) members of Marshfield Clinic Health System’s Virtual Data Warehouse population (i.e., members of Security Health Plan of Wisconsin and/or residents of the Marshfield Epidemiologic Study Area [24 darker shaded postal code areas]), or (2) medically-homed to the Marshfield Clinic Health System (i.e., primary care provider assigned to them, or with a preponderance of primary care visits having occurred at a Marshfield Clinic Health System center over the past three years).