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Studying Disease Patterns

This is a new edition of a text which first appeared ten years ago. Although in broad outline the book is unchanged, developments in epidemiological techniques and a widening field of interest have forced a radical revision in detail. At the same time a subtle change in style makes for easier reading and readier comprehension. The traditional introduction through the classic studies of Snow, Farr, and Lind, for example, is retained together with the standard methods of using measurement and comparison of the frequency of disease in different groups of the population to unravel the web of causation. But there is more emphasis on recent developments-for example, studies of migrant groups and the statistical analysis of observed clustering of disease in time or space. Chronic diseases, and especially cancer, now absorb attention; and methods such as the cohort analysis of mortality that were originally used to study tuberculosis are shown to be equally appropriate in seeking environmental causes of Parkinsonism and peptic ulcer as well as cancer of the lung. There is a timely discussion of the distinction between deaths associated with and attributable to cigarette smoking and of the statistical aspects of the analysis and interpretation of results from both retrospective and prospective studies. A new section deals with the border areas between genetics and epidemiology. It covers, for example, the use of twin studies to separate the influence on disease of genetic endowment and environmental factors and the relation of birth order and parental age to monogolism. Inevitably, the choice of subjects reflect the work and interest of the authors. There is, for example, little about the developments in the techniques of clinical surveys of the prevalence of chronic disease. But such selective omissions in no way detract from the merit of an introduction to the subject which can be warmly commended to all students of preventive medicine. D. D. REID