Occupational radiation studies: status, problems, and prospects.

At least 350,000 workers at U.S. radiation facilities are being followed up to monitor their mortality experience, with particular reference to cancer. Although these studies are expensive, they are needed from the standpoint of public health and radiation protection; they also provide a useful check that the risk extrapolation models based on high dose data are not seriously out of line. Unfortunately, there are a number of problems in interpreting radiation worker studies that stem mainly from the fact that the expected magnitude of effects is small because of the low doses. Problems of falsely positive effects caused by chance or by study biases are difficult to distinguish from real effects. Dose-effect analyses and pooled analyses from several studies offer some improvements in assessing the risk from low doses but do not obviate all the problems. Future studies should explore whether there are biological markers of exposure, damage, or susceptibility that would improve our power to assess individual risk.