CONTENTS Letter of transmittal__ Previous publications in this series. Part 1. Background on epidemiology. B. Uses of epidemiology C. Examples of historical contributions_ D. Historical summary of uses of epidemiology E. Changing world patterns of diseases.. F. Life expectancy climbs. _ G. World aging studies needed.. H. Aging process suggests basic research. I. Long-term benefits of basic research. J. Universal need for basic research. K. Worldwide opportunities for genetic and other basic research.. L. Broad gauged understanding needed.. M. The World Health Organization and epidemiology N. Role of national vital and health statistics systems.. O. Epidemiological activities throughout the United States. P. Summary of uses of epidemiology Part 2. Selected worldwide opportunities for epidemiological research by disease category. B. Heart disease. A. Cancer.__ C. Diabetes.. D. Arthritis E. Sickle-cell anemia_ F. Peptic ulcer_.. G. Dental diseases_ H. Mental illness__ I. Neurological disorders_. Part 3. Conclusion.. Index.. LIST OF CHARTS Page III 1 1 2 2 7 9 10 11 13 13 14 15 15 18 29 31 32 33 35 37 39 51 53 Figure 1. Life expectancy of world population___ disease.. Figure 4. Cardiovascular death rates compared with fat consumption___ Figure 6. Death rates, selected countries, by type of cardiovascular dis ease__ Figure 7. Diabetes death rate for total population by sex for Japan and Figure 8. Incidence and distribution of cerebral vascular disease in the Figure 9. Death rates from cerebral vascular disease, selected countries__ North versus South... Figure 11. Multiple sclerosis in selected countries... Part 1 BACKGROUND ON EPIDEMIOLOGY Each civilization, it has been said, makes its own diseases. The first half of the 20th century, with its many social, industrial, and economic changes, confirms that present civilization follows the time-tried pattern. A list of significant changes in the 20th century might include: Newly discovered and improved types of transportation; Development of new knowledge for infectious disease control; Increasing numbers of older people; and Emerging importance of chronic disease as a health factor. These changing patterns of living are universal. They contribute to the worldwide problem of disease in a wide variety of ways. The network of sources, causes, and carriers of disease is so intricate that it suggests the need for a special effort (a) aimed at defining the questions and (b) pinpointing the answers to diseases and disabling conditions that occur on a worldwide basis. One of the most interesting and hopeful avenues of approach to the control and eradication of today's major diseases is through world epidemiology. 1 A. EPIDEMIOLOGY DEFINED Epidemiology has been defined as a science of mass phenomena of diseases and human defects. It describes significant varieties of these phenomena in time and place. It draws upon statistical methods and theory, all phases of medicine, and the natural sciences to give a true picture of the occurrence, distribution, and types of diseases or defects. As an illustration, the epidemiological study of hypertension (high blood pressure) seeks-as in similar studies-to evaluate the influence of diverse genetic and environmental factors upon the occurrence and severity of the disease. No one has succeeded in demonstrating specifically what causes high blood pressure. Yet marked differences in the incidence and severity of the disease in different population groups support the hope that epidemiological studies may succeed in defining the causative factors. By contrast with clinical medicine, the unit of study in epidemiology is the population or group, not the individual. Deaths, or any other event, are studied only if information can be obtained or inferred about the population in which the events occurred. The population may be a small and well-defined group in a municipality, may include a whole country or even an entire continent. The epidemiologist, therefore, as opposed to the clinician who deals in cases, is concerned with cases as they occur in their population. He may start with a 1 Other terms frequently used to denote this general discipline, but implying somewhat differing meanings are medical geography and ecology. The more accepted term, epidemiology, is, however, used throughout this publication. Ecology is referred to on p. 11. |