Trace elements among Iowa pesticide applicators

描述（由申请人提供）： 农业健康研究（AHS）是一项既定的、正在进行的前瞻性队列研究，旨在研究爱荷华州和北卡罗来纳州农业暴露（如农药使用）与施用者疾病之间的关系。爱荷华州的AHS涉及36,793名有执照的农药施用者，加上21,773名直接或间接接触农药和其他农业接触的配偶。农民的前列腺癌发病率和死亡率较高，使其成为高风险群体。农民中潜在暴露的机制尚不清楚，因此对这一美国人亚群的研究很重要。目前的文献表明，砷、镉和低硒水平与前列腺癌有关，但研究并不一致。 我们建议在现有的AHS中进行一项巢式病例对照试点研究，通过爱荷华州癌症登记处（ICR）对前列腺癌的半快速报告进行鉴定，以检查在脚趾甲中发现的微量元素，包括砷，镉和硒，所有长寿指标，沿着其他符合此分类的微量元素。我们将比较86例前列腺癌病例和172例对照组（年龄、完成饮食调查和最近PSA测试的频率匹配）的这些元素。我们将使用中子活化分析（NAA）来分析目标微量元素。我们证明检查其他微量元素是一项具有成本效益的假设生成子研究。 这项试点研究的第二个目的是检查有效性的砷和硒测量脚趾甲相比，标准的问卷测量饮食硒和砷农药诊断前收集在这个队列。在居住稳定的人群中，微量元素的生物标志物可能是一个很好的暴露措施，减少了对农药和复杂的食物频率问卷（FFQ）的长期详细列表的问卷调查的需要。

DESCRIPTION (provided by applicant): The Agricultural Health Study (AHS) is an established, on-going prospective cohort study examining the relationship between agricultural exposures, such as pesticide use, and disease among applicators in Iowa and North Carolina. The AHS in Iowa involves 36,793 licensed pesticide applicators, plus 21,773 spouses who are exposed either directly or indirectly to pesticides and other agricultural exposures. Prostate cancer incidence and mortality are higher among farmers, making this a high-risk cohort. The mechanism of potential exposure among farmers is unclear, so research into this subgroup of Americans is important. Current literature suggests associations with prostate cancer and arsenic, cadmium and low selenium levels but studies have not been consistent. We propose a nested case-control pilot study of incident prostate cancer within the existing AHS, identified through semi-rapid reporting of prostate cancers by the Iowa Cancer Registry (ICR), to examine trace elements found in toenails including arsenic, cadmium and selenium, all long-lived indicators, along with other trace elements that fit into this classification. We will compare these elements in 86 incident prostate cancer cases to 172 controls (frequency matched on age, completion of the diet survey, and a recent PSA test) from within the AHS cohort. We will use neutron activation analysis (NAA) to analyze for the targeted trace elements. We justify examining the other trace elements as a cost efficient, hypothesis generating sub-study. A secondary aim of this pilot study is to examine the validity of arsenic and selenium measured in toenails compared with standard questionnaire measurements of dietary selenium and arsenic pesticides collected prior to diagnosis in this cohort. In residentially stable populations, biomarkers of trace elements may be a good measure of exposure reducing the need for questionnaires with long detailed lists of pesticides and complex food frequency questionnaires (FFQs).