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Agricultural Health Study/Pesticide Exposure Study (AHS)
Scientific Problem and Policy Issues
Despite low mortality and low cancer incidence rates overall, farmers may experience excess risk of specific cancers and other adverse health outcomes, as observed in some retrospective epidemiological studies of agricultural workers. Farmers, their families, and other pesticide applicators may have contact with pesticides and a variety of other potentially hazardous substances (e.g., solvents, fuels, oils, exhaust, dust, agriculturally-specific microbes). Previous epidemiologic studies of farmers, other agricultural workers, and agricultural pesticide applicators have been limited by inadequate or retrospective exposure information.
Research Approach
Limitations of these previous studies are being addressed through the Agricultural Health Study (AHS), a prospective epidemiological study to quantify the cancer and non-cancer risks in the agricultural community and to study the relationship between agricultural pesticide exposures and disease. The study uses questionnaires to provide information regarding pesticide use, work practices, and other agricultural exposures, as well as information on other activities that may affect either exposure or risk for a large (more than 89,000) cohort of licensed agricultural pesticide applicators and their spouses in Iowa and North Carolina.
Information derived from the study questionnaires is used to develop exposure-classification procedures for subsequent investigation of associations between pesticide exposure and specific diseases. Exposure measurement data are needed to assess these questionnaire-based exposure-classification procedures. The U.S. EPA conducted the AHS Pesticide Exposure Study (PES) to assess the exposure-classification procedures developed from the AHS questionnaire data and to better understand factors leading to pesticide exposures for agricultural pesticide applicators and their families. The AHS PES was an exposure-measurement field study for a subset of agricultural pesticide applicators and participating family members in the larger AHS cohort.
Results and Implications
The study is providing real-world exposure data for improving exposure and risk assessments for agricultural pesticide applicators and their families by
- Improving survey questionnaires and the exposure-classification procedures based on data from the questionnaires;
- Increasing the power of the AHS epidemiological study through improved exposure assessments;
- Assessing critical exposure pathways and factors influencing applicator exposures to agricultural pesticides;
- Assessing how exposures for families of agricultural pesticide applicators compare to exposures for the general population.
The research results will be used to improve health-risk assessments in the larger AHS epidemiological study. The results may also provide information on how pesticides can be handled more safely to reduce the exposure risks to farm-workers and their families. Study findings may be used by pesticide-safety educators to improve training programs for agricultural pesticide applicators and other pesticide handlers.
Research Collaboration and Publications
The AHS is a collaborative effort between the National Cancer Institute (NCI), the National Institute of Environmental Health Sciences (NIEHS), and the U.S. Environmental Protection Agency (U.S. EPA). The EPA’s Office of Research and Development, National Exposure Research Laboratory (ORD/NERL) and the Office of Pesticide Programs are the primary EPA collaborators for the study.
Principal Investigator: Kent Thomas