ABSTRACT
Epidemiolo-gical data may be used in a variety of ways in risk assessment, principally in hazard identification and exposure—response analysis. This chapter reviews basic concepts in the design and interpretation of epidemiological studies, focusing on their application in risk assessment. Major epidemiological study designs have contributed substantially to understanding the etiology of human cancer. Cohort studies are studies in which a defined group of people are followed for a period of time. Epidemiological studies may be hypothesis testing or hypothesis generating. Ecological studies, in which correlations are made at a group level are often used to generate hypotheses about exposure—disease associations and typically cannot do more than that. The case—control design has played an important role in the understanding of lifestyle, infections, and familial risk factors for cancer, and in generating and testing hypotheses about environmental and occupational causes.
