Studies of Populations Exposed to Environmental Sources

对受核试验或事故放射性尘降物影响的人口进行研究是本项目的一个主要重点。1986年发生在乌克兰的切尔诺贝利核反应堆事故导致白俄罗斯、乌克兰西北部以及与俄罗斯接壤省份的儿童患甲状腺癌的人数空前增加。在能源部（DOE）和核管理委员会（NRC）的协助下，NCI组织了对白俄罗斯的39,000名儿童和乌克兰的34,000名儿童的长期跟踪研究。到目前为止，大约有2万名受试者的甲状腺进行了筛查。在白俄罗斯进行的一项关于甲状腺癌的病例对照研究中，根据个人剂量估计，证明了甲状腺癌与切尔诺贝利剂量之间具有统计学意义的剂量特异性联系。居住在俄罗斯特恰河沿岸的村民长期受到来自马亚克核设施的外部和内部辐射。正在对大约28,000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。目前的工作重点是追踪原始人口以获取重要状态信息；以及剂量重建，使用辐射效应研究联合协调委员会的剂量估计。辐射流行病学处对哈萨克斯坦塞米巴拉金斯克原子弹武器试验场附近受到放射性沉降物严重和轻微照射的村庄的3 000名居民进行了甲状腺筛查研究，这些居民在受到照射时年龄在20岁以下。来自美国和哈萨克斯坦的一组医生通过超声和针活检进行了甲状腺筛查。目前正在努力进行剂量重建，并将估计的个人剂量与问卷调查数据和剂量的生物标志物联系起来。为了弥合高剂量矿工研究和低剂量住宅氡研究之间的差距，该处在中国开展了肺癌和室内高水平氡的综合病例对照研究。对现在和以前的住所进行了为期一年的氡测量。结果支持室内氡暴露增加肺癌风险，可能等于或超过基于矿工数据的推断。

Studies of populations exposed to fallout from nuclear tests or accidents are a major focus of this project. The Chernobyl nuclear reactor accident in Ukraine in 1986 has led to an unprecedented increase in thyroid cancer among children in Belarus, northwestern Ukraine, and bordering Russian provinces. With the assistance of the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC), NCI has organized long-term follow-up studies of 39,000 children in Belarus and 34,000 in Ukraine. To date, the thyroid glands of approximately 20,000 subjects have been screened. In a case-control study of thyroid cancer in Belarus, with individual dose estimates, a statistically significant dose-specific link between thyroid cancer and Chornobyl dose was demonstrated. Villagers 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 28,000 people who received large doses of radiation from the radioactive waste dumped into the river. Current efforts focus on tracing the original population for vital status information; and on dose reconstruction, using the Joint Coordinating Committee for Radiation Effects Research dose estimates. The Radiation Epidemiology Branch conducted a thyroid screening study of 3,000 residents of heavily exposed and lightly exposed villages near the Semipalatinsk Atomic Bomb Weapons Test Site in Kazakstan exposed to radioactive fallout, who were under 20 years of age at exposure. Screening of thyroid glands by ultrasound and needle biopsy was performed by a team of physicians from the U.S. and Kazakstan. Efforts are currently underway for dose reconstruction and to link the estimated individual doses to questionnaire data and biological markers of dose. To bridge the gap between the high-dose miner studies and low-dose residential radon studies, the Branch conducted a comprehensive case-control study of lung cancer and high levels of indoor radon in China. Year-long radon measurements were made in current and former residences. Results support increased lung cancer risks with indoor radon exposures which may equal or exceed extrapolations based on miner data.