Determining health risks of new hazards - we can do better!

Efficient prevention of industrial health problems is based on the availability of a human dose-response relationships and the factors that modify them. These can be used to estimate an individual's risk of adverse effects given an appropriate measure of his or her exposure intensity and its duration. Unfortunately, an individual's risk cannot be measured directly because risk is a property of groups of exposed individuals and must be determined by epidemiologic studies. As a result, when a new industry is developed around new materials, we usually cannot directly determine the health risks the materials may pose. Additionally, we cannot be reasonably certain of the human risks using data from animal, cell or other tests. Humans interact with environmental/occupational exposures in complex behavioral, biochemical, genetic and physiologic ways that are not well simulated in the lab. Society is also reluctant to limit the development of new materials, processes and ideas that may lead to important and exciting applications. One consequence of all of these limitations is a billion dollar industry can develop before enough human subjects have received enough exposure to do a useful epidemiologic study. If we better integrate multidisciplinary studies of new hazards, we can do better and quicker risk characterizations. A diagram of the relationship between environmental and occupational exposure and the development of disease is shown in Fig. 1. A broad range of disciplines is needed to do a complete evaluation of these risk relationships, as shown along the bottom line of Fig. 1. However, the study of risks has become compartmentalized and disconnected. We liken what we are studying to an elephant. As in the Indian story of the six blind men and the elephant 2) , each disciplinary group of scientists studies a small portion of the elephant with simplifying assumptions to make the problem tractable. The exposure and behavioral scientists, toxicologists, clinical scientists, and epidemiologists each argue the truth of their findings and may imply that the divergent findings of other disciplines are misleading or mistaken. Yet, each group has made important and relevant observations about aspects of occupational health problems. However, as the complexity has grown and exposure levels have decreased, single specialty studies have become less informative, and important opportunities for needed collaborations have been missed. In addition, there are risk assessment and policy experts who attempt to integrate the findings with further assumptions as they try to understand the " big …