Radiation-exposed populations: who, why, and how to study

Everyone is exposed to natural and manmade ionizing radiation that can originate from sources in the environment and in medical and occupational settings. There is notable variation, however, among individuals and across populations in the types of sources of radiation and in the frequency, level, and duration of exposure. Adverse health effects associated with radiation exposure have been known for decades, and ionizing radiation exposure has been linked with a broad range of different types of cancer and benign neoplasms as well as birth defects, reproductive effects, and diseases of the circulatory, hematologic, and neurologic systems. Our present understanding of radiation-related health risks derives primarily from multidisciplinary health risk (epidemiologic) studies that provide the key information on radiation-associated health outcomes, quantify radiation-related disease risks, and enhance understanding of mechanisms of radiation-related disease pathogenesis. Such information is central to quantifying risks in relation to benefits; addressing public concerns, including societal and clinical needs in relation to radiation exposure; and providing the database needed for establishing recommendations for radiation protection. Because of the importance of determining risks compared to benefits for all situations where exposure to ionizing radiation might result, it is useful for planning new health risks studies to categorize exposed populations according to the sources and types of radiation. This paper describes a wide range of populations exposed to radiation and the motivation and key methodological criteria that drive the rationale and priority of studying such populations. Also, discussed are alternative methods for evaluating radiation-related health risks in these populations, with a major focus on epidemiologic approaches. This paper concludes with a short summary of major highlights from radiation epidemiologic research and important unanswered questions.Introduction of Exposed Populations (Video 1:29, http://links.lww.com/HP/A22).