Studies of Populations Exposed to Environmental Sources

儿童时期接触切尔诺贝利事故放射性尘埃的良性和恶性甲状腺疾病1986年乌克兰切尔诺贝利核反应堆事故污染了白俄罗斯、乌克兰西北部和俄罗斯边境省份的大部分地区。在白俄罗斯进行的一项病例对照研究，对个人剂量进行了估计，结果表明，甲状腺癌与切尔诺贝利事故相关沉降物的辐射剂量之间存在统计学上的显著联系。在能源部和核管制委员会的协助下，国家癌症研究所对白俄罗斯和乌克兰儿童时期接触过切尔诺贝利事故放射性沉降物的人进行了良性和恶性甲状腺疾病的长期跟踪研究。迄今为止，每个国家约有12 000名受试者每两年接受一次甲状腺筛查。根据乌克兰第一次筛查的数据进行的甲状腺癌患病率分析已在JNCI上发表。JCEM接受了一份关于自身免疫性甲状腺炎的论文：《受倾倒在俄罗斯马亚克核设施附近的Techa河中的放射性废物影响的人口的癌症死亡率》。目前正在对大约3万人的癌症死亡率进行评估，这些人接受了倾倒在河里的放射性废物的大剂量辐射。目前的工作重点是提高数据质量，追踪人口以获取生命状况信息，以及进行统计分析。癌症死亡率和辐射剂量之间的联系已经被观察到。以甲状腺结节作为衡量哈萨克斯坦境内儿童时期接触塞米巴拉金斯克试验场核试验沉降物的3 000名居民的辐射风险的指标：通过超声筛查确定的甲状腺结节患病率，作为主要结果变量，用于评估受核弹试验放射性沉降物影响的哈萨克斯坦3000名农村居民的沉降物暴露影响1949年至1962年在塞米巴拉金斯克试验场附近进行的试验。94%的受试者在1949年时未满18岁，或者在测试期间出生。31%的受试者（18%的男性和39%的女性）检测到一个或多个直径为3 mm或以上的流行结节。由国家癌症研究所和莫斯科生物物理研究所联合开发的一种新的剂量重建算法被用来估计来自外部和内部放射性沉降物衍生辐射源的个人甲状腺剂量，主要依据是居住历史和在受污染牧场上放牧的奶畜的估计牛奶消费量。经性别和筛选年龄调整后，发现外部和内部剂量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统计分支来获得新的信息，这些方法考虑到估计剂量中的随机误差，这些努力的重点是不确定性的来源，特别是那些涉及通过牧场到牛奶食物链摄入的碘放射性同位素的内剂量的来源。在中国农村进行的一项肺癌综合病例对照研究中，高水平的室内氡增加了肺癌的风险，将来自该研究的烟草数据与来自其他肺癌和烟草的大型病例对照研究的数据合并，以评估吸烟强度对风险的影响。皮肤癌和其他癌症的风险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。

Benign and Malignant Thyroid Disease Among Those Exposed as Children to Fallout from the Chornobyl AccidentThe 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 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 has organized long-term follow-up studies of benign and malignant thyroid disease among those exposed as children to fallout from the Chornobyl accident in Belarus and in Ukraine. To date, the thyroid glands of approximately 12,000 subjects in each country have been screened biennially. A prevalence analysis of thyroid cancer based on data from the first screening in Ukraine has been published in JNCI. A paper on autoimmune thyroiditis has been accepted by JCEM.Cancer Mortality Among the Population Exposed to Radioactive Waste Dumped in the Techa River Adjacent to the Mayak Nuclear Facility in RussiaVillagers living along the banks of the Techa River in Russia were exposed to chronic external and internal radiation from the Mayak nuclear facility. Cancer mortality is being evaluated in a cohort of approximately 30,000 people who received large doses of radiation from the radioactive waste dumped into the river. Current efforts focus on improving data quality, tracing the population for vital status information, and on statistical analyses. Ans association between cancer mortality and radiation dose has been observed. 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: Thyroid nodule prevalence, determined by ultrasound screening, was used as the main outcome variable for evaluating the effects of 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. Ninety-four percent of subjects were under 18 years of age in 1949 or were born during the period of testing. One or more prevalent nodules, 3 mm or more in diameter, were detected in 31% of all subjects (18% of males and 39% of females). 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.Lung Cancer and High Levels of Indoor Radon in ChinaIn collaboration with the Biostatistics Branch, tobacco data from a comprehensive case-control study of lung cancer in rural China in which high levels of indoor radon increased lung cancer risk was pooled with data from other large case-control study of lung cancer and tobacco, in order to evaluate effect modification of risk by smoking intensity.Ultraviolet Sunlight Exposure, Ionizing Radiation, and Risk of Skin and Other CancersExposure to ultraviolet (UV) radiation from sunlight plays a predominant role in the etiology of melanoma and non-melanoma skin cancer.