What about the workers? An update

Epidemiological studies of nuclear industry workers are of substantial importance to understanding the risk of cancer consequent to low-level exposure to radiation, and these studies should provide vital evidence for the construction of the international system of radiological protection. Recent studies involve large numbers of workers and include health outcomes for workers who accumulated moderate (and even high) doses over prolonged periods while employed during the earlier years of the nuclear industry. The interpretation of the findings of these recent studies has proved to be disappointingly difficult. There are puzzling patterns of results involving the period of first employment and monitoring for radionuclide intakes, depending on the particular study examined. Explaining these patterns is crucial for a reliable understanding of results in terms of occupational radiation exposure. In this paper, an updated review of nuclear worker studies is presented in the context of these patterns of results, making use of the latest relevant results. It is apparent that the strikingly raised risks for mortality from solid cancers for workers hired in later years reported from the International Nuclear Workers Study (INWORKS) is effectively confined to workers at five nuclear facilities in the USA, and that the notable variation of risks in INWORKS between workers monitored or not for radionuclide intakes is driven by UK workers. These are the areas where effort must be concentrated before a confident derivation of radiation risk estimates can be obtained from these nuclear worker studies.