Epidemiology in risk assessment for regulatory policy

Abstract

THE TWENTIETH century has seen the rapid evolution of many new fields concerned with protecting public health. Epidemiology and risk assessment have several of the features common to these new fields, and important differences. Both are needed to make the difficult decisions required in setting standards for levels of toxic agents in the workplace and environment. They differ in their aims, orientation, and time scale. According to Lilienfeld and Lilienfeld [2], epidemiology is “the study of the distribution of a disease or a physiological condition in human populations and of the factors that influence this distribution” (italics added). By contrast, health risk assessment denotes research and evaluation to characterize the probability of physical harm to humans attributable to a particular agent or group of agents. While the distribution of disease provides the focus for epidemiologic research, concern for adverse effects of specific toxicants drives risk assessment. Moreover, while epidemiologic studies proceed at the glacier-like pace needed to mobilize large staffs of support personnel and to monitor large populations over long periods of time, risk assessment activities acquire the urgency felt by regulators, who must make decisions (including decisions to postpone decisions) today. Most important, while epidemiology is a scientific field that draws upon medicine, demography, and statistics, risk assessment is a hybrid of science and policy that draws not only upon fields such as epidemiology, toxicology, chemistry and engineering, but also upon psychology, politics, economics, law and social justice. These inherent differences in emphasis, timing, and nature complicate the role played by epidemiology in risk assessment for regulatory policy. In 1985, this role is still largely one of epidemiology’s uncharted galaxies. In the sections below, I review the role’s history, and the reasons why it will continue to play an essential part in regulatory decisionmaking. The role has placed epidemiologic findings and epidemiologists at the center of political controversies, and I discuss the positive and negative side effects of this new visibility. Finally, I explore ways to prevent the negative side effects and ways to increase the utility of epidemiologic data for regulatory risk assessment.