Cancer Risk & Environ. Exposures to Nitrate,Pesticides,

癌症风险

• 批准号: 6755605
• 负责人: MARY H WARD
• 金额: --
• 依托单位: DIVISION OF CANCER EPIDEMIOLOGY AND GENETICS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6755605
• 关键词: United States; agriculture; cancer risk; chemical carcinogen; chemical carcinogenesis; chemical related neoplasm /cancer; clinical research; environmental exposure; environmental toxicology; human data; neoplasm /cancer epidemiology; nitrates; pesticide biological effect; pesticides; rural area; water pollution; water supply

Risk factors for cancer from agricultural exposures in the ambient environment are studied to estimate the contribution of these environmental exposures to cancer in the rural population. Rural populations have exposures to pesticides and nitrates in drinking water that are intermediate between occupationally-exposed groups and the general population. Case-control studies have been conducted on non-Hodgkin's lymphoma and cancers of the brain, bladder, colon, rectum, stomach, esophagus, pancreas, and kidney. Databases of water contaminants, gathered for routine monitoring purposes, are being used to estimate past exposures via public water supplies to individuals in these case-control studies. Nitrate levels in public water supplies in Iowa were not associated with risk of bladder and pancreas cancer. However, higher intakes of dietary nitrite were associated with an increased risk of pancreas cancer. Overall, drinking water nitrate levels were not associated with risk of colon cancer; however, specific subgroups with increased nitrosation ability were at increased risk. Elevated nitrate levels in public drinking water supplies were associated with an increased risk of non-Hodgkin's lymphoma in Nebraska. An analysis of nitrate in drinking water in Minnesota where exposure levels were lower found no association. Elevated nitrate in public water supplies in Nebraska was associated with an increased risk of glioma in women but not men. This hypothesis is being investigated further in a recently completed case-control investigation of non-Hodgkin's lymphoma in Iowa, Seattle, and the Detroit area. The issue of nitrate as a cancer risk factor is being pursued further in an ecologic study of census-block groups in the Platte River Valley of Nebraska and Colorado, where elevated nitrate levels are among the highest in the country. Nitrate levels in private wells are being estimated using data on land cover, livestock feedlot locations, soil type, and other information. We are also developing new approaches, and improving existing methods, of exposure assessment in studies of general environmental exposures, with a focus on pesticides and nitrate. These are required to better estimate risk and to detect the relatively small increases in risk often encountered in such studies. Geographic information systems (GIS) are being utilized for developing new approaches to estimating indirect exposure to pesticides and for estimating exposure to nitrate in private wells. Remote sensing data (satellite imagery) and historical records were used to estimate the population in Nebraska and Iowa potentially exposed to agricultural pesticides through the proximity of their homes to agricultural land treated with pesticides. This approach is also being used to improve pesticide exposure assessment in California in conjunction with the State pesticide use reporting database. Validation studies are underway in Iowa and California to determine the relationship between pesticide levels in the home and the proximity to agricultural land where pesticides have been applied. Pesticides A feasibility study using remote sensing data and a GIS to estimate indirect exposure to pesticides demonstrated that using available data, accurate historical crop maps could be produced and that these could be linked to pesticide use data to estimate probabilities of indirect exposure to agricultural pesticides. A total of 24% of the study population in an agricultural area were determined to live within 500 meters of crop fields likely to have been treated with pesticides. This was the first study to estimate the prevalence of potential indirect exposure to agricultural pesticides in the general population. Further work in this area by our collaborators included the development of a method to automate crop mapping from satellite imagery. The method was found to be successful at classifying crops into two categories: corn and other crop types, over a 15 county area of Nebraska. We are continuing to refine the GIS-based approach to estimating agricultural pesticide exposure by incorporating information from a pesticide drift model. A validation study is underway in Iowa to compare agricultural pesticide levels in carpet dust samples with several GIS-based exposure metrics including one that incorporates information on wind direction and pesticide drift. With collaborators in California, we are planning to evaluate agricultural pesticide use near residences as a risk factor for childhood leukemia in an ongoing study. Carpet dust samples will be analyzed for pesticides, and information about the current and historical location of crops near residences will be determined. Using a GIS, residential proximity to specific industries, hazardous waste sites, and specific chemical releases as reported by the Environmental Protection Agency's Toxic Release Inventory will be evaluated in an ongoing case control study of bladder cancer in New England. The first steps have been to evaluate the feasibility of geocoding past residential histories from a pilot study in New Hampshire and to determine the historical locations of specific industries associated with bladder cancer risk.

研究了周围环境中农业暴露的癌症风险因素，以估计这些环境暴露对农村人口癌症的影响。农村人口接触农药和饮用水中的硝酸盐，介于职业接触群体和一般人口之间。已经对非霍奇金淋巴瘤和脑癌、膀胱癌、结肠癌、直肠癌、胃癌、食道癌、胰腺癌和肾癌进行了病例对照研究。在这些病例对照研究中，为例行监测目的收集的水污染物数据库被用来估计个人过去通过公共供水的暴露情况。爱荷华州公共供水中的硝酸盐水平与膀胱癌和胰腺癌的风险无关。然而，饮食中亚硝酸盐的摄入量增加与胰腺癌的风险增加有关。总体而言，饮用水硝酸盐水平与结肠癌风险无关;然而，亚硝化能力增加的特定亚组风险增加。内布拉斯加州公共饮用水供应中硝酸盐水平升高与非霍奇金淋巴瘤风险增加有关。明尼苏达州饮用水中的硝酸盐暴露水平较低，分析发现没有关联。内布拉斯加州公共供水中硝酸盐含量升高与女性而非男性患神经胶质瘤的风险增加有关。最近在爱荷华州、西雅图和底特律地区完成的一项非霍奇金淋巴瘤病例对照研究正在进一步探讨这一假说。在内布拉斯加州和科罗拉多州的普拉特河谷进行的一项生态学研究中，硝酸盐作为癌症风险因素的问题正在进一步探讨，那里的硝酸盐水平是全国最高的。私人威尔斯水井中的硝酸盐含量正在利用土地覆盖、牲畜饲养场位置、土壤类型和其他信息的数据进行估计。我们还在一般环境暴露研究中开发新的暴露评估方法，并改进现有方法，重点是农药和硝酸盐。这些都需要更好地估计风险，并检测出相对较小的风险增加往往遇到这样的研究。目前正在利用地理信息系统开发新的方法，以估计间接接触农药的情况和估计接触私人威尔斯的硝酸盐的情况。遥感数据（卫星图像）和历史记录被用来估计内布拉斯加州和爱荷华州的人口可能暴露于农业农药，因为他们的家园接近农药处理过的农田。这种方法也被用于改进加州的农药暴露评估，并与州农药使用报告数据库相结合。验证研究正在爱荷华州和加州进行，以确定家中农药水平与施用农药的农田附近之间的关系。 农药 一项利用遥感数据和地理信息系统估计间接接触农药的可行性研究表明，利用现有数据，可以制作准确的历史作物地图，并将这些地图与农药使用数据联系起来，以估计间接接触农药的概率。在农业区，共有24%的研究人口被确定居住在可能使用杀虫剂的农田500米范围内。这是第一项估计一般人群间接接触农药的流行率的研究。我们的合作者在这一领域的进一步工作包括开发一种根据卫星图像自动绘制作物地图的方法。该方法被发现成功地将作物分为两类：玉米和其他作物类型，超过内布拉斯加州的15个县。我们正在继续完善基于地理信息系统的方法，通过纳入农药漂移模型的信息来估计农业农药暴露。爱荷华州正在进行一项验证研究，将地毯灰尘样本中的农药水平与几个基于GIS的暴露指标进行比较，其中包括一个结合了风向和农药漂移信息的指标。 与加州的合作者，我们计划在一项正在进行的研究中评估住宅附近使用农药作为儿童白血病的危险因素。将对地毯灰尘样本进行杀虫剂分析，并确定住宅附近作物当前和历史位置的信息。 使用地理信息系统，住宅接近特定的行业，危险废物的网站，和特定的化学品释放的环境保护局的有毒物质释放清单报告将进行评估，在新英格兰膀胱癌的病例对照研究。第一步是从新罕布什尔州的一项试点研究中评估对过去的居住历史进行地理编码的可行性，并确定与膀胱癌风险相关的特定行业的历史位置。