Occupational epidemiology: problems in reaching an overview

Need for precise estimation of small occupational hazards has required the development of new epidemiological techniques, including the combination of the results of many different studies. Data for 10 cohorts of nuclear energy workers support the belief that occupational hazards have been small, but are insufficient to provide precise estimates of their size. The few that can be used to relate risk quantitatively to dose are compatible with the risks predicted from the experience of persons exposed acutely to high doses. Several unsolved biological problems complicate accurate predictions. (author)