Environmental contaminants and low-level cancer risks: perceptions and scientific strategies

Scientific and public perceptions concerning low-level lung cancer risks may vary. Recently the public has been more convinced of causal links between low-level risk agents and cancer, and more interested in prevention of environmental exposures, especially those induced by others. Thus, scientific strategy is partly driven by the public need to resolve issues concerning the importance of low-level exposures and risks. Further, investigators have been challenged intellectually to create methodologies in order to study some of these relationships further, and scientific curiosity has been stimulated by the difficulties of pursuing such investigations. The importance of host characteristics, including the genetic bases of susceptibility, has become a major theme. Likewise, host behaviour has become a potential positive factor (e.g. diet) as well as a negative factor in the risk model for low-level agents. This paper discusses some of the information available on low-level agents and some of the methodological issues involved in studying them. The importance of measuring exposure as well as response is stressed, especially multi-pollutant exposures and interactions with host behaviour.