The Agricultural Health Study (AHS) is a long-term prospective study of potential health effects associated with pesticides and other agricultural exposures. The study is funded by the National Cancer Institute and the National Institute of Environmental Health Sciences, with collaboration from the US Environmental Protection Agency and the National Institute for Occupational Safety and Health. We are examining cancer incidence and other health endpoints in licensed pesticide applicators, spouses and children from North Carolina (NC) and Iowa (IA). Over a 3-year period (1993-7), we enrolled more than 57,000 licensed applicators, representing 82% of eligible private pesticide applicators (largely farmers) in IA and NC and 43% of commercial applicators from Iowa. About 40% of the private applicators also completed a more detailed take-home questionnaire covering farming practices and health. Nearly 32,000 spouses of farmer applicators enrolled and 2/3 also provided data on reproductive health, including information on all children under age 21 at time of enrollment. About 70% of participants completed the first five-year follow-up telephone interview (1999-2003) and the response rate was similar for the second follow-up interview (2005-2010). A third health follow-up started in summer 2013 and is expected to be completed at the end of 2014. In addition to updating farming history and lifestyle exposures, the primary focus is on identifying incident cases of respiratory, neurologic, and autoimmune diseases as well as other outcomes reflecting the older age of this cohort. The cohort is regularly followed through linkage with population-based cancer registries in IA and NC and vital statistics, including state death records and the National Death Index. Buccal-cell samples for DNA were collected from participants at the time of the first follow-up interview. Additionally, buccal samples are collected on an ongoing basis from participants who develop cancers and other conditions of interest to facilitate nested studies of gene-pesticide interactions. A dietary assessment (food frequency questionnaire) also was completed by participants during the first follow-up. In-depth pesticide exposure assessment has been carried out for selected chemicals in targeted samples of the cohort. Results have been used to validate study questionnaires and inform exposure classification. Non-cancer outcomes of particular interest have included neurological diseases and symptoms (Parkinson's disease, hearing loss, depression, neurobehavioral function, and suicide, amyotrophic lateral sclerosis), respiratory and allergic outcomes (asthma, rhinitis, and chronic bronchitis), cardiovascular disease (heart attack, stroke), diabetes (gestational and adult onset), autoimmune diseases (rheumatoid arthritis, lupus, and Sjogren's syndrome), age-related macular degeneration, fatal injury, and adverse reproductive outcomes (infertility, fibroids and endometriosis). In the Growth and Puberty (GAP) Study, a pilot study to assess the feasibility of measuring early puberty markers (hormone levels in urine and saliva, height velocity, Tanner staging), we enrolled and followed 60 children. Hormone assays were recently completed and their use in predicting puberty onset is being explored. Data analysis continues for the Farming and Movement Evaluation (FAME) study while new cases of Parkinson's disease continue to be captured (see report by F Kamel). Data collection for an in-depth study of respiratory diseases (The Lung Health Study) is nearing completion (see report by S London). The AHS cohort continues to participate in large data pooling projects through the NCI-sponsored Cohort Consortium. In addition, the Agricultural Health Study is one of the founding members of the Agricultural cohort consortium (AGRICOH) and we hope to use this collaboration to enhance our ability to assess rare exposures and outcomes. To date, the Agricultural Health Study has published nearly 200 scientific papers, including about 20 papers in the past year. These publications cover a range of health conditions such as cancer, Parkinsons disease, depression, and respiratory outcomes. For example, in a recent analysis among spouses of private pesticide applicators, we reported that sun exposure might be associated with a modest lower risk for developing breast cancer (Engel et al. Environ Health Perspect 2014). Another analysis of data from 55,875 pesticide applicators suggests associations between specific pesticides such as DDT, lindane and non-Hodgkin lymphoma and its subtypes (Alavanja et al. Occup Environ Med 2014). AHS investigators have also been working on non-cancer outcomes. We recently reported potential associations between pesticide exposure and depression among male private applicators (Beard et al. Environ Health Perspect 2014);on the other hand, among spouses of these farmers, we did not see these specific associations (Beard et al. Environ Res 2014). We also reported that dietary intake of poly-unsaturated fat was associated with lower Parkinsons disease risk, and dietary fats modified the association of Parkinsons risk with pesticide exposure (Kamel et al. Parkinsonism Relat Disord. 2014 ). Finally among wives of the private applicators, we found that exposures to specific organochlorines and certain organophosphates were associated with higher risk for diabetes (Starling et al. Occup Environ Med. 2014). Over the years, the Agricultural Health Study has contributed to our knowledge on potential health effects of exposures that are associated with pesticides use and other farming activities. This continuously serves our ultimate goal to improve the health of US farmers and their family members.
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