Resources: Epidemiology

Epidemiology is the study of disease in groups, hence is the key scientific underpinning of Public Health. It provides the research methods for measuring the disease burden in the population, assessment of disease causation and the benefits of interventions to reduce the disease burden. There is not room in this introduction to do more than point to some of the key issues.

Epidemiology for the Uninitiated is an excellent primer, and although a little dated stands the test of time as providing a basis for epidemiological methods (by Cogon, Rose and Barker). Here is part of the first section on What is Epidemiology:

Epidemiology is the study of how often diseases occur in different groups of people and why. Epidemiological information is used to plan and evaluate strategies to prevent illness and as a guide to the management of patients in whom disease has already developed.

Like the clinical findings and pathology, the epidemiology of a disease is an integral part of its basic description. The subject has its special techniques of data collection and interpretation, and its necessary jargon for technical terms....

All findings must relate to a defined population

A key feature of epidemiology is the measurement of disease outcomes in relation to a population at risk. The population at risk is the group of people, healthy or sick, who would be counted as cases if they had the disease being studied. For example......

Epidemiology as a basis for Public Health The way of measuring the causes of disease depends on epidemiology, which many people agree is the fundamental discipline of Public Health. However, as this quote makes clear, more evidence than just available from epidemiologic research is required:
"In epidemiology, causality is defined as: "The relating of causes to the effects they produce. Most of epidemiology concerns causality... It must be emphasized, however, that epidemiologic evidence by itself is insufficient to establish causality, although it can provide powerful circumstantial evidence.” (from John M Last (ed.), A Dictionary of Epidemiology, 3rd ed, Oxford University Press, 1995.)"

An excellent presentation, Web of Causation; Exposure and Disease Outcomes, by Songer in the Epidemiology Supercourse, discusses the role of epidemiology in ascribing causation really well - look out for the (Bradford) Hill criteria in the presentation (slides 25-31).