:: Nuclear workers
Many studies have been carried out of cancer among nuclear industry workers. Most of the exposures to these workers were in line with international standards. In contrast, many workers at the Mayak plant in Russia received high doses over a protracted period, and raised (but poorly quantified) risks have been seen for several types of cancer in this group. Some of the worker studies have been limited by relatively small population sizes and/or short follow-up periods. The larger studies include a combined analysis of abaut 95.000 workers in Canada, the US and the UK, and cohorts of over 100.000 nuclear workers in Japan (although with a short follow-up) and the UK. Most of the analyses have looked only at mortality. There has been some variation in the findings, which may be due in part to low statistical precision. However, mortality has often been lower than in the general population, due probably to factors associated with selection into and continuation of employment. The larger studies have tended to indicate an increasing trend in leukaemia risk with increasing dose, whereas the evidence for a dose-related increase in solid tumour risks has generally been less. However, the confidence limits for these trend estimates have been relatively wide, and encompass risks extrapolated from the Japanese atomic-bomb survivors as well as a range of values, both higher and lower. More precise information will be obtained from an ongoing international collaborative study of cancer risk in nuclear industry workers.
At present, the findings from these studies do not indicate the need to modify current radiation protection measures for workers.