The Role of Epidemiology

Abstract

Epidemiology may be defined as the study of the determinants of the incidence and prevalence of disease. This relatively simple definition has some extremely widespread implications. It immediately suggests that epidemiology may be used to identify the cause of disease, but it must be remembered that it is most unusual that there is a single cause for a disease without any other confounding or intervening factors playing a part. Thus the examination of the causation of disease may involve investigators in an extremely wide range of studies unravelling a complex tangle of factors. The consideration of factors influencing the prevalence of disease adds a different perspective to the role of epidemiology; the prevalence of disease (the measure of the extent to which a disease exists in a population at a point in time) is a combination of the incidence of the condition, the cure rate and the fatality from this condition. In order, therefore, to study the determinants of the prevalence of a condition, information about the incidence, the natural history of the disease and the impact of the health-care system on the disease is required. This involves studying the cause of disease, the identification of disease patterns, the population’s attitudes to disease, their tendency to seek cure, the range of care provided and the impact of such care on the disease.