Confirmation of Systemic Autoimmune Diseases in the Agricultural Health Study

Farming-related exposures (including pesticides and silica) may contribute to the etiology of autoimmune diseases. However, associations between autoimmune diseases and farming have not been extensively investigated, and exposure data in the currently available studies is extremely limited. One of the major challenges in conducting population-based research on autoimmune diseases is case ascertainment. Self-report of previous diagnosis has been shown to be very unreliable. This protocol outlines a strategy to confirm self-reported diagnoses of systemic autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus, scleroderma, and Sjogren syndrome) within the Agricultural Health Study (AHS) cohort. The confirmed cases will constitute a refined case group to allow etiologic analyses of pesticides and other farming-related exposures as possible risk factors for these diseases using data that have already been collected. The codes can also be used in a nested case-control study that could be designed to collect additional exposure data (for example, on silica-related exposures).