Contemporary Epidemiology: Perspectives and Uses' * Background Rockefeller Foundation to support the establishment Epidemiology is concerned with the study of health, of schools of public health administratively and, unfor- disease, and health services in groups of people or tunately to a growing degree, intellectually and scien- populations in contrast to the study of other aspects of tifically separate from schools of medicine. The prob- these phenomena in individuals, cells, and molecules. lems are recounted in Professor John Evans' recent Translated literally, epidemiology means "that which report written for the Foundation (2). The disparity is upon the people." Its intellectual siblings are demog- between the population's burden of illness and the raphy, economics, statistics, and sociology, all of health care establishment's priorities for education, re- which had the same origins in the XVIlth century. search, and services has serious consequences for de- Epidemiology is an essential tool for measuring the veloped countries, yet in the developing world, these burden of illness and suffering in the population being consequences are often disastrous. The Foundation's served by the entire health care enterprise, for assessing current hypothesis, held also by other agencies and by the relative costs, risks, and benefits of a wide variety leaders in both developed and developing countries, of interventions designed to improve health, for eval- is that one way to restore to medical science and edu- uating the impact of health services and practice on cation a population-based perspective and eventually the populations' health status, and for developing clues influence the setting of priorities and allocation of re- to the web of causality which influences diseases of sources at institutional and national levels, is to train all types. established young clinical faculty members in epi- The term "epidemiology" was first given wide cur- demiology and to do so in settings where credible cli- rency by the clinicians who founded the London Epi- nicians both care for patients and conduct epidemiolog- demiological Society in 1850 (1). Over the years, how- ical studies. Although the fellows the Foundation sup- ever, epidemiology's clinical origins have been forgot- ports receive a Master of Science degree (or in some ten, and until recently most contemporary clinicians instances a Ph.D.) and are equipped to undertake inde- have had no exposure to the population-based perspec- pendent research on their return home, the main con- tive. Their views are usually grounded in educational cern is the change of attitudes, practices, and priorities. experiences that have been confined largely to tertiary It is too early in the course of the planned evaluation care hospitals and that concentrate on molecular and to judge, but solid evidence now exists in Brazil, the cellular processes. Many, if not most clinicians (mainly People's Republic of China, and Thailand, for exam- those in academic clinical departments) have had little, ple, of substantial changes in attitudes and interests if any, exposure to the concepts, methods, and appli- associated with the return of these promising young cations of epidemiology. It is these academic clini- leaders to their home universities and the establishment cians, especially professors of medicine and surgery, of clinical epidemiology units within the medical who treat politicians and administrators the world over, schools. give advice, and exert a powerful influence based on Epidemiology is the one science that can shift the what they know and experience in university teaching balance in the health care establishment's priorities hospitals. They are unfamiliar with the great bulk of from a predominant preoccupation with individual the population's health problems which exist outside transactions between doctors and their patients to a hospital walls where people live, work, suffer, and broader collective concern on the part of all health die. These distortions of viewpoint and experience have professionals for the care of entire populations. At the resulted in gross imbalances in the organization of very least, epidemiology should help sensitize med- health services, in the training of health manpower, icine to society's health needs and prepare for demands and in the setting of priorities. The net effect is the which will inevitably find expression through the polit- absurd misallocation of resources, intolerable ineq- ical process. In this global arena, the simple definition uities in access to care, and escalating health care costs of epidemiology as "the study of that which is upon which threaten to bankrupt societies. the people" will suffice; more restrictive definitions Much of this isolation from the population-based that refer to "distributions of diseases" or to the perspective is attributable to an earlier decision of the "causes of epidemics" seem outmoded and unhelpful in the broader context in which contemporary health . 'Presented by Dr. Kerr L. White, former Deputy Director for Health problems are now being viewed. Sciences, The Rockefeller Foundation (New York, USA), at the Seminar on Uses and Perspectives of Epidemiology, Buenos Aires, Argentina, 7-10 The epidemiologists' opportunities to contribute November 1983. 13 have been restricted not only by their fragmentation The intellectual tools provided by epidemiology en- into camps concerned with communicable diseases, able all clinicians to examine not only the history of noncommunicable diseases, environmental problems, disorders presented by their patients but also the natural population dynamics, or health services, for example, history of medical care and its outcomes. Both the but also by the arbitrary limitations each camp places hospital-based specialist or consultant and the gen- on the applicability of a rather simple set of ideas and eralist or family physician can undertake epidemiolog- methods to an ever-broadening array of contemporary ical and operational studies, or at least learn to use health problems. The history of epidemiology is replete and interpret the kinds of clinical and management with tales of the strong views expressed by the com- information that is increasingly available to them. In- municable disease epidemiologists with respect to the deed, it can be argued that the medical practice of the legitimate 'application of "their" methods to noncom- future in most industrialized countries will find groups municable diseases and by both these groups with re- of general and specialized doctors with their related spect to the use of epidemiological principles in study- hospitals and facilities taking responsibility for the care ing population trends and evaluating health services. of entire populations, not just of those who present Even now, questions are raised about the appropriate themselves as patients. Their concern and efforts will use of epidemiological methods in the study of such focus on detecting health problems at the earliest pos- contemporary problems as delinquency, social de- sible stage and, when feasible, preventing their occur- viance, emotional deprivation, drug abuse, attempted rence in high-risk groups. To better manage their pa- suicide, and loneliness or even in the study of doctors' tients' health care, general or primary care physicians prescribing patterns or patient's attitudes toward keep- and specialists and consultants will use clinical and epi- ing appointments or complying with treatment regimes. demiological information about them in conjunction There is a definite need for a theoretical framework with data on the populations from which they come. that does not require all noxious agents to be physical, Similarly, health services administrators and the statis- chemical, or biological and that leaves room for such ticians and epidemiologists with whom the clinical complex deleterious influences on health as noise pol- physicians work will be responsible for developing lution, jet fatigue, occupational stress, domestic vio- health information systems to serve multiple purposes. lence, inadequate parenting, and sexual strife. These will include the clinical management of patients Of all the disciplines that constitute the scientific as well as the management of medical practices, health . basis for health care, epidemiology should be the last centers, hospitals, and related resources that serve de- to resort to defensive postures and restrictive practices. fined populations. The health problems and care pro- The fact that laboratory sciences have concentrated on vided will need to be monitored both within medical cellular activities, hospital medicine on the more florid practices and institutions and for local, regional, and manifestations of acute diseases, general practice on national populations. It is one of the tasks of epide- symptomatic treatment of individuals, and traditional miologists to design these health information systems public health on limited services for categorical health so that clinical and administrative decision-making can problems is no justification for epidemiology to limit be based on a reliable flow of useful information. its view of the origins and distribution of health, dis- ability, and distress in populations. Each of these com- Future Challenges ponents has a legitimate role in any contemporary health services system that employs epidemiology di- What follows is a brief consideration of the range rectly or indirectly for at least part of