Studies of Populations Exposed to Environmental Sources

受切尔诺贝利事故放射性尘降物影响的儿童患良性和恶性甲状腺疾病1986年发生在乌克兰的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中良性和恶性甲状腺疾病的长期跟踪研究。迄今为止，每两年对每个国家约12,000名受试者的甲状腺进行筛查。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。一篇关于自身免疫性甲状腺炎的论文被JCEM接受。俄罗斯马亚克核设施附近特恰河倾倒放射性废物暴露人群中的癌症死亡率生活在俄罗斯特恰河沿岸的村民长期暴露在马亚克核设施的外部和内部辐射下。正在对大约3万人进行癌症死亡率评估，这些人从倾倒入河中的放射性废物中接受了大剂量辐射。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。已观察到癌症死亡率与辐射剂量之间的关系。甲状腺结节作为在塞米巴拉金斯克试验场作为儿童受核试验沉降物影响的3000名哈萨克斯坦居民的辐射风险衡量指标：通过超声筛查确定甲状腺结节患病率，作为主要结果变量，用于评估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所产生的放射性沉降物对3000名哈萨克斯坦村庄居民的影响。94%的受试者在1949年未满18岁或在测试期间出生。31%的受试者（18%的男性和39%的女性）检测到一个或多个直径大于3mm的普遍结节。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。中国肺癌和高水平室内氡中国肺癌和高水平室内氡与中国生物统计处合作，将中国农村地区高水平室内氡增加肺癌风险的综合病例对照研究的烟草数据与其他大型肺癌和烟草病例对照研究的数据进行汇总，以评估吸烟强度对风险的影响。紫外线照射、电离辐射和皮肤及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.