In this lecture, students will learn about the recent advances in epidemiology relevant to health risk assessment (RA). As mentioned in Lecture 3, toxicity assessment, exposure assessment, and risk characterization are now the three subprocesses involved in the revised RA scheme. The newer scheme is different from the one first formulated (National Research Council, 1983) only in that hazard identification and dose-response assessment are now treated as one process. In either case, epidemiologic studies by far provide the most relevant evidence for hazard identification. This strength is offset to a great extent, however, by the difficulties associated with obtaining and interpreting epidemiologic information since such is derived from observational studies.

Epidemiology involves the association of diseases to risk factors and human exposures. Accordingly, here the students are also expected to learn some of the recent developments in human exposure assessment, specifically those pertinent to the recent advances in epidemiology or RA. One recent advance in epidemiology especially noteworthy is the use of biomarkers, which are physiological, biochemical, or molecular alterations measurable in biologic media such as human cells, fluids, or tissues (Hulka, 1990).

The use of biomarkers in epidemiologic studies has now become a popular assessment tool. In the last part of this lecture, students will learn how and why biomarkers can be used to extend our understanding of the steps between exposure and disease occurrence, and about the limitations of this use.