Studies of Populations Exposed to Environmental Sources of Radiation

<font color="#990000" <b>儿童受切尔诺贝利事故放射性尘降物影响的良性和恶性甲状腺疾病</b></font><br> 1986年乌克兰切尔诺贝利核反应堆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。在白俄罗斯进行的一项病例对照研究，根据个人剂量估计，表明甲状腺癌与与切尔诺贝利事故有关的沉降物产生的环境辐射剂量之间存在统计学上显著的联系。在能源部（DOE）和核管理委员会（NRC）的协助下，NCI组织了对白俄罗斯和乌克兰切尔诺贝利事故放射性尘降物的儿童的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。基于乌克兰首次筛查数据的甲状腺癌患病率分析已在JNCI上发表，并在cancer上发表了关于肿瘤病理的描述性论文。在JCEM上发表了一篇关于自身免疫性甲状腺炎的论文，在临床内分泌学上发表了一篇关于低暴露组抗体水平的论文，在美国流行病学杂志上发表了一篇关于滤泡腺瘤的剂量反应分析。其他一些手稿，包括一篇关于子宫内暴露的偶发甲状腺癌和甲状腺功能减退的手稿即将提交。这些项目目前正准备从主动筛查过渡到其他形式的后续工作，扩大现有的国家癌症登记处。<br><br> <font color="#990000" <font font><br>居住在俄罗斯特恰河沿岸的村民长期受到马亚克核设施排放到河中的放射性废物的外部和内部环境辐射。正在对大约3万名从受污染的河流中接受低至中等剂量辐射的人进行癌症死亡率评估。目前的工作重点是提高数据质量，追踪人口的重要状态信息，以及统计分析和手稿准备。已经观察到实体癌和白血病死亡率与辐射剂量之间的关系。<br><br> <font color="#990000"><b>作为辐射风险指标的3000名哈萨克斯坦居民在塞米巴拉金斯克试验场作为儿童暴露于核试验沉降物中的甲状腺结节</b></font></br>甲状腺结节患病率，由超声筛查确定；作为主要结果变量，用于评价1949-1962年期间在附近塞米巴拉金斯克试验场进行的核弹试验产生的放射性沉降物对哈萨克斯坦3000名村庄居民的环境辐射沉降物暴露的影响。NCI和莫斯科生物物理研究所联合开发了一种新的剂量重建算法，主要基于居住史和在受污染牧场放牧的奶牛的估计牛奶消费量，用于估计来自外部和内部放射性尘降源的个体甲状腺剂量。在调整筛查时的性别和年龄后，发现外剂量和内剂量都与结节患病率显著且独立相关。目前的努力包括通过使用焦点小组访谈和应用考虑到估计剂量随机误差的统计方法获得新信息，这些努力侧重于不确定性来源，特别是涉及通过从牧场到牛奶的食物链摄入的碘放射性同位素的内部剂量。研究了13个基因的多态变异对辐射剂量-反应关系的影响及其对甲状腺结节发病的主要影响。发现XRCCI变异与辐射剂量和甲状腺结节风险相互作用。<br><br> <font color="#990000"辐射生物剂量学</b></font><br>定期对科学文献进行审查，以确定用于估计过去职业和环境辐射照射剂量的最新技术。这些数据被用来为目前受辐照人群的流行病学研究提供信息。切尔诺贝利，Techa River， x射线技术人员)可能丢失剂量的地方，以估计剂量不确定性或验证估计剂量。<br><br> <font color="#990000" <br><b >阳光照射、电离辐射与皮肤和其他癌症的风险</b></font><br>来自阳光的紫外线辐射暴露在黑色素瘤和非黑色素瘤皮肤癌的病因中起主要作用。越来越多的证据表明，黑色素瘤和两种主要的非黑色素瘤皮肤癌（即基底细胞癌和鳞状细胞癌）与不同的紫外线照射模式（即全面、慢性和急性间歇性）有关，但这种关系的性质很复杂，尚未完全了解。我们最近完成了一项研究，以评估问卷为基础的阳光照射数据的有效性，使用组织学评估阳光相关的皮肤损伤。此外，也有人认为，阳光照射可能对非霍奇金淋巴瘤（NHL）和一些其他形式的癌症有保护作用。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，以评估与这种暴露相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相关辐射暴露估计值进行修正。<br /><br />< font color="#990000" <br> <b>NHANES III：前瞻性维生素研究</b></font><br> NHANES III数据集测量了约20,000人的维生素D水平，是一个独特的资源，可以调查维生素D与特定死亡原因之间关系的许多问题。这个队列包括实际的维生素D测量和大约2253例死亡，其中1072例死于循环系统疾病，536例死于癌症。我们已经完成了基线维生素D与所有癌症死亡率之间关系的分析，并发表了一份手稿。随访时间延长，死亡人数增加了60%。对癌症结果的分析正在扩展数据集中进行。<br /><br />

<font color="#990000"><b>Benign and Malignant Thyroid Disease Among Those Exposed as Children to Fallout from the Chornobyl Accident</b></font><br> The Chernobyl nuclear reactor accident in Ukraine in 1986 contaminated large parts of Belarus, northwestern Ukraine, and bordering Russian provinces. A case-control study in Belarus, with individual dose estimates, demonstrated a statistically significant link between thyroid cancer and environmental radiation dose from fallout related to the Chornobyl accident. With the assistance of the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC), NCI organized follow-up screening studies of benign and malignant thyroid disease among those exposed as children to fallout from the Chornobyl 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. A prevalence analysis of thyroid cancer based on data from the first screening in Ukraine has been published in JNCI, and a descriptive paper on the pathology of the tumors has appeared in Cancer. A paper on autoimmune thyroiditis has been published in JCEM, a paper on antibody levels among the low-exposed group has appeared in Clinical Endocrinology, and dose-response analysis of follicular adenoma is in the American Journal of Epidemiology. A number of other manuscripts, including one on incident thyroid cancers on the in utero exposed and on hypothyroidism are close to submission. The projects are currently preparing to transition from active screening to other forms of follow-up widening the existing national cancer registries.<br><br> <font color="#990000"><b>Cancer Mortality Among the Population Exposed to Radioactive Waste Released in to the Techa River Adjacent to the Mayak Nuclear Facility in Russia</b></font><br> Villagers living along the banks of the Techa River in Russia were exposed to chronic external and internal environmental radiation from radioactive waste released into the river by the Mayak nuclear facility. Cancer mortality is being evaluated in a cohort of approximately 30,000 people who received low to moderate radiation doses from the contaminated river. Current efforts focus on improving data quality, tracing the population for vital status information, and on statistical analyses and manuscript preparation. Associations between solid cancer and leukemia mortality and radiation dose have been observed.<br><br> <font color="#990000"><b>Thyroid Nodules as a Measure of Radiation Risk Among a Population of 3000 Residents in Kazakhstan Exposed as Children to Fallout from Nuclear Testing at the Semipalatinsk Test Site</b></font></br> Thyroid nodule prevalence, determined by ultrasound screening, was used as the main outcome variable for evaluating the effects of environmental radiation fallout exposure in a population of 3000 village residents in Kazakhstan affected by radioactive fallout from nuclear bomb tests at the nearby Semipalatinsk Test Site during 1949-1962. A new dose-reconstruction algorithm, developed jointly by NCI and the Institute of Biophysics in Moscow, was used to estimate individual thyroid doses from external and internal sources of fallout-derived radiation, based mainly upon residential history and estimated consumption of milk from dairy animals grazing on contaminated pasture. Both external and internal dose were found to be significantly and independently associated with nodule prevalence after adjustment for sex and for age at screening. Current efforts, which include obtaining new information through the use of focus group interviews and application of statistical methods that take account of random errors in estimated dose, are focused on sources of uncertainty, especially those involving internal dose from radioactive isotopes of iodine ingested through the pasture-to-milk food chain. Polymorphic variants in 13 genes were studied for effect modification of the radiation dose-response relation and main effects on thyroid nodule risk. A variant in XRCCI was found to interact with radiation dose and thyroid nodule risk.<br><br> <font color="#990000"><b>Radiation Biodosimetry</b></font><br> Periodic reviews of the scientific literature are conducted to identify the most current techniques used to estimate doses from past exposure to occupational and environmental radiation. These data are used to inform current epidemiologic studies of irradiated populations (eg. Chernobyl, Techa River, X-ray technologists) where doses may be missing, to estimate dose uncertainty or validate estimated doses.<br><br> <font color="#990000"><b>Ultraviolet Sunlight Exposure, Ionizing Radiation, and Risk of Skin and Other Cancers</b></font><br> Exposure to ultraviolet (UV) radiation from sunlight plays a predominant role in the etiology of melanoma and non-melanoma skin cancer. There is accumulating evidence linking melanoma and two major non-melanoma skin cancers (i.e., basal cell carcinoma and squamous cell carcinoma) to different patterns of UV exposure (i.e., total, chronic and acute intermittent), but the nature of the relationship is complex and not fully understood. We have recently completed a study to evaluate the validity of questionnaire-based sun exposure data using histologically assessed sun-related skin damage. Furthermore, it has also been suggested that sunlight exposure may have a protective effect for non-Hodgkin lymphoma (NHL) and some other forms of cancer. 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 this 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 sun-related radiation exposures. <br /><br /> <font color="#990000"><b>NHANES III: Prospective Vitamin Study</b></font><br> The NHANES III data set with measured vitamin D levels on about 20,000 people is a unique resource that allows investigation of many issues on the relationship between vitamin D and specific causes of mortality. This cohort includes actual vitamin D measurements and about 2253 deaths, of which 1072 are circulatory disease deaths and 536 are all cancer deaths. We have completed analysis of the relationship between baseline vitamin D and all cancer mortality, with a manuscript published. The Follow-up has been extended- with 60% more deaths. Analyses of cancer outcomes are being under taken in the extended dataset.<br /><br />