Studies of Populations Exposed to Environmental Sources of Radiation

正在对居住在俄罗斯乌拉尔南部捷查河沿岸的约3万人的癌症死亡率进行评估，这些人长期受到马亚克核设施排放到捷查河中的放射性废物的环境辐射照射。目前的工作重点是利用最近的随访数据和剂量测定系统进行统计分析，并准备稿件。已观察到实体癌和白血病死亡率之间存在显著的剂量-反应关系。乌克兰的切尔诺贝利事故污染了白俄罗斯、乌克兰西北部和与俄罗斯接壤省份的大部分地区。两项有个人剂量估计的病例对照研究表明，甲状腺癌与事故相关沉降物的环境辐射剂量之间存在统计学上显著的联系。研究中心及其合作者在白俄罗斯和乌克兰的儿童时期受事故放射性尘降物影响者中组织了良性和恶性甲状腺疾病的后续筛查研究。每两年对每个国家约12 000名受试者的甲状腺进行筛查，乌克兰为4个周期，白俄罗斯为3个周期。这些项目已从主动筛查过渡到利用现有的国家癌症登记处进行其他形式的随访。我们已经完成了一项基于队列的神经胶质瘤全基因组关联研究，包括来自队列联盟的18项研究，目的是确认与神经胶质瘤风险相关的基因区域，确定在队列设置中可能更明显的遗传易感性的新区域，并基于队列中可用的协变量数据进行靶向基因环境分析。器官剂量计算计算机程序的开发计算机程序是基于蒙特卡罗传输技术与计算人类幻影相结合，为暴露于辐射事故或恐怖事件的个体提供器官剂量估计。为预防放射或核事件后的不良健康影响而采取适当的医疗对策，对受辐射人群的辐射防护至关重要，在涉及孕妇及其后代时，这是科学、医疗和公众特别关注的问题。1986年4月26日至1987年2月28日期间，在白俄罗斯出生的数千名儿童在子宫内和生命早期就受到切尔诺贝利事故的影响。这项研究将建立一个约2 500名白俄罗斯人的队列，这些人在子宫内和生命早期就受到切尔诺贝利沉降物的放射性碘和其他放射性同位素的照射，重建内部和外部辐射照射对甲状腺的剂量，确定甲状腺癌和其他甲状腺疾病，并评估辐射剂量反应。NHANES III：前瞻性维生素研究NHANES III数据集测量了大约2万人的维生素D水平，这是一个资源，可以调查维生素D与特定死亡原因之间的关系。这个队列包括实际的维生素D测量和大约2253例死亡，其中近900例是癌症死亡。在一项已发表的研究中，我们发现不同种族/民族的循环25(OH)D与癌症死亡率之间没有关系。该数据集还允许检查25(OH)D与我们正在审查的其他循环激素（例如睾酮）之间的关系。暴露于阳光中的紫外线（UV）辐射在黑色素瘤和非黑色素瘤皮肤癌的病因学中起着主要作用，但两者之间关系的本质尚不完全清楚。我们最近完成了来自7万多名美国放射技术人员的终身紫外线辐射相关暴露的问卷收集，并进行了分析，以评估与暴露有关的特定形式癌症的风险。我们还计划评估与电离辐射职业暴露相关的皮肤癌风险是否可以通过问卷得出的紫外线辐射暴露估计值进行修正。这项研究的基础是对1949年至1962年期间在塞米巴拉金斯克核试验场进行的核试验所产生的放射性沉降物对哈萨克斯坦儿童的辐射照射和甲状腺疾病进行的现有研究。内部和外部辐射源对这一人群的高甲状腺剂量提供了一个独特的机会，可以量化和比较这两种类型作为单一人群中甲状腺疾病的危险因素。利用焦点小组访谈进行了一项实地研究，以调查可能影响个人甲状腺辐射剂量的沉降物影响地区典型乡村生活的各个方面。我们收集了影响两个不同民族儿童甲状腺辐射剂量的因素的回顾性信息，包括牛奶和奶制品的消费、在核试验时的季节性放牧和奶牛的补充喂养、户外活动的时间以及建筑物提供的辐射屏蔽。这些数据将填补当前剂量重建方法中的关键空白，并应改进剂量估计，为评估和量化剂量学不确定性和风险估计中的相关偏差提供基础。这项以人群为基础的流行病学研究旨在评估1986年4月切尔诺贝利核事故释放的放射性物质造成的产前暴露于碘-131可能导致的不良生殖结果。研究人群是一个定义明确的队列，包括来自乌克兰北部污染地区的2,582对母子，最初是为了调查良性和恶性甲状腺疾病的风险，通过对后代进行深入的临床筛查检查，并在2003-2006年与母亲进行结构化访谈。目前研究的生殖结果数据是通过检索和回顾队列成员的产前、分娩和新生儿记录来确定的。数据记录在由研究妇科医生设计的摘要表格上，并在分析数据库中登记。胎儿甲状腺碘-131剂量的个体估计可用于所有受试者。对一组数据完整的队列成员（N=1167）进行了统计分析，以检验胎儿I-131剂量与新生儿人体测量学和妊娠期的关系。初步结果显示剂量依赖关系与头围和妊娠长度。我们目前正在进行更广泛的分析，以实现这些初步发现。我们还在扩大工作范围，探索辐射对子宫内受辐射后代生殖功能/生育能力的影响。

Cancer Mortality Among Populations Exposed to Radioactive Waste in the Techa River by Mayak Nuclear Facility Cancer mortality is being evaluated in a cohort of approximately 30,000 people who lived by the banks of the Techa River in the Southern Urals of Russia and had protracted environmental radiation exposure from radioactive waste released into the river by the Mayak nuclear facility. Current efforts focus on statistical analyses using the recent follow-up data and dosimetry system and manuscript preparation. Significant dose-response relationships have been observed for both solid cancer and leukemia mortality. Chernobyl Thyroid Study in Belarus/Ukraine The Chernobyl accident in Ukraine contaminated large parts of Belarus, northwestern Ukraine, and bordering Russian provinces. Two case-control studies with individual dose estimates demonstrated a statistically significant link between thyroid cancer and environmental radiation dose from fallout related to the accident. REB and collaborators organized follow-up screening studies of benign and malignant thyroid disease among those exposed as children to fallout from the accident in Belarus and in Ukraine. The thyroid glands of approximately 12,000 subjects in each country have been screened biennially for four cycles in Ukraine and three cycles in Belarus. The projects have transitioned from active screening to other forms of follow-up using existing national cancer registries. Cohort-based GWAS of Glioma We have completed a cohort-based genome wide association study of glioma including 18 studies from the Cohort Consortium, with the aim of confirming gene regions associated with glioma risk, identifying new regions of genetic susceptibility that may be more apparent in a cohort setting, and conducting targeted gene-environment analyses based on the covariate data available from cohorts. Development of Computer Program for Organ Dose Calculations The computer program is based on Monte Carlo transport technique coupled with computational human phantoms to provide organ dose estimates for individuals exposed to radiological accidents or terrorist events. Dose reconstruction and Health Effects of In-utero and Early Life Radiation Exposure Appropriate medical countermeasures for prevention of adverse health effects following radiological or nuclear incidents are critical to radiation protection of exposed populations, and are of particular scientific, medical and public concern when pregnant women and their offspring are involved. Several thousands of children born in Belarus during the period from April 26, 1986 through February 28, 1987, were exposed in utero and in early life as a result of the Chernobyl accident. This study will establish a cohort of about 2,500 Belarusian individuals exposed in utero and in early life to radioactive iodine and other radioactive isotopes from Chernobyl fallout, reconstruct doses to the thyroid gland from internal and external radiation exposure, ascertain thyroid cancer and other thyroid diseases and assess radiation dose-responses. NHANES III: Prospective Vitamin Study The NHANES III data set with measured vitamin D levels on about 20,000 people is a resource that allows investigation of the relationship between vitamin D and specific causes of mortality. This cohort includes actual vitamin D measurements and about 2253 deaths, of which nearly 900 are cancer deaths. In a published study of this data we found no relationship between circulating 25(OH)D and cancer mortality across racial/ethnic groups. The dataset also allows examination of relationships between 25(OH)D and other circulatinf hormones (e.g., testosterone) which we are reviewing. Skin Cancer in Radiologic Technologists Exposure to ultraviolet (UV) radiation from sunlight plays a predominant role in the etiology of melanoma and non-melanoma skin cancer, but the nature of the relationship is not fully understood. We recently completed questionnaire-based collection of lifetime UV sun-related radiation exposure from more than 70,000 U.S. radiologic technologists and have undertaken analyses to assess risks of specific forms of cancer in relation to exposure. We also plan to evaluate whether skin cancer risks associated with occupational exposures to ionizing radiation might be modified by questionnaire-derived estimates of UV radiation exposures. Study to Improve Thyroid Doses from Fallout Exposure in Kazakhstan This builds on an existing study of radiation exposure and thyroid disease among individuals in Kazakhstan exposed during childhood to radioactive fallout from nuclear tests conducted at the Semipalatinsk Nuclear Test Site between 1949 and 1962. High thyroid doses to this population from both internal and external radiation sources present a unique opportunity to quantify and compare the two types as risk factors for thyroid disease in a single population. A field study using focus group interviews has been conducted to investigate aspects of typical village life in areas affected by fallout that might influence individual radiation doses to the thyroid gland. We collected retrospective information about factors influencing radiation dose to the thyroid gland in children of two distinct ethnic groups, including milk and milk product consumption, seasonal practices of pasturing and supplemental feeding of dairy animals at the time of the nuclear tests, time spent outdoors, and radiation shielding provided by buildings. These data will fill key gaps in the current dose-reconstruction methodology and should result in improved dose estimates, providing the basis for evaluating and quantifying dosimetric uncertainty and related biases in risk estimates. NICHD_NCI_Health Effects of in Utero Exposure to I-131 in Chernobyl Fallout The population-based epidemiologic study was designed to evaluate potential adverse reproductive outcomes associated with prenatal exposure to Iodine-131 as a result of radioactive releases from the April 1986 Chernobyl nuclear accident. The study population is a well-defined cohort of 2,582 mother-child pairs from contaminated areas of northern Ukraine, originally assembled to investigate the risk of benign and malignant thyroid disease through in-depth clinical screening examinations of the offspring and structured interviews with the mothers carried out in 2003-2006. Data for the current study of reproductive outcomes were ascertained by retrieving and reviewing cohort members' prenatal, delivery and newborn records. Data were recorded on an Abstract Form designed with the help of study gynecologists and registered in analytic data base. Individual estimates of fetal thyroid Iodine-131 dose are available for all subjects. Statistical analyses to examine the relationship of fetal I-131 dose with neonatal anthropometrics and length of gestation have been carried out on a subset of cohort members with complete data (N=1167). Preliminary results show dose-dependent relationships with head circumference and gestational length. We are currently carrying out more extensive analyses to pursue these initial findings. We are also extending the work to explore radiation effects on reproductive function/fertility among the in-utero exposed offspring.