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，旨在调查爱荷华州和北卡罗来纳州农药使用者的农业暴露与疾病之间的关系。爱荷华州的AHS涉及36,793名有执照的农药施用者，以及21,773名直接或间接接触农药和其他农业接触的配偶。前列腺癌在农民中的发病率和死亡率更高，使这一群体成为高危人群。农民中潜在的接触机制尚不清楚，因此对这一美国亚群的研究很重要。目前的文献表明，前列腺癌与砷、镉和低硒水平有关，但研究并不一致。 我们建议对现有AHS中发生的前列腺癌进行嵌套式病例对照试点研究，通过爱荷华州癌症登记中心(ICR)对前列腺癌的半快速报告来检查脚趾甲中发现的微量元素，包括砷、镉和硒，这些都是长寿指标，以及符合这一分类的其他微量元素。我们将86例前列腺癌病例中的这些因素与AHS队列中172名对照组(在年龄、饮食调查完成情况和最近的PSA测试中匹配的频率)进行比较。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、产生假设的子研究。 这项初步研究的第二个目的是检查脚趾甲中测量的砷和硒的有效性，并与在该队列中诊断前收集的膳食硒和砷杀虫剂的标准问卷测量进行比较。在居住稳定的人群中，微量元素的生物标记物可能是减少接触的一个很好的措施，减少了对带有长长的详细杀虫剂清单的问卷和复杂的食物频率问卷(FFQ)的需求。

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).