Epidemiologic Methods

During the past several years there has been a growing interest in epidemiologic investigation, particularly in the field of non-infectious diseases. Although a few books devoted to epidemiology are available, for the most part the subject has been presented in public health and preventive medicine textbooks, in which methodology has often taken second place to a descriptive epidemiology of specific diseases. The present volume considers the subject as a science and, as suggested by the title, it is constructed on a basic framework of epidemiologic methodology. Major emphasis is placed on concepts and principles, most of which are well established in the field of infectious disease epidemiology, and their modification and application for use in present day studies of non-infectious diseases. The epidemiologic concepts of direct and indirect causal association and various concepts of classification and grouping of illnesses are well presented in abstract and diagramatic forms followed by examples drawn from established epidemiologic experience. The important areas of terminology, methods of measurement and data collection are clearly presented with, as far as possible, an intentional avoidance of purely biostatistical techniques. In fact, in the preface it is suggested that statistical knowledge is not required in order to understand the principles of epidemiology, but "the reader intending to put these principles into practice would do well to sentence himself to a term with a book of elementary statistics." The major portion of the book is concerned with various axes of classification (e.g. time, place and person) and their sub-divisions most commonly used in analyzing associations between characteristics of the population under study and its entire environment, temporal and spatial, in relation to disease patterns. Instead of describing the total epidemiologic picture of individual illnesses, chapters or sections are devoted to specific characteristics and for each of these several examples have been drawn from a wide variety of diseases. Two clearly written chapters on analytic epidemiology (cohort studies and case history studies) will prove of considerable interest and value to all who have experienced difficulty in understanding the problems and limitations of such studies and have had doubts about their proper interpretation in view of conflicting testimonials (e.g. lung cancer and cigarette smoking). The final chapter entitled "Experimental Epidemiology" is limited to human experiments, controlled, uncontrolled and "natural." Only fleeting mention is made (in an earlier chapter) of the "old" experimental epidemiology of Greenwood, Topley and Wilson. One wonders why this field, animal as well as human, failed to receive more attention in a book which provides such complete coverage of the methods of epidemiologic