ABSTRACT
Modern epidemiology is “the study of the distribution and determinants of disease frequency in human populations”. It is one of the foundations of the health sciences in that it provides the methods to gather knowledge about constellations of candidate causes of illness, based on detailed observations in populations. The distinction between causes and pathogenesis of illness is marked by an important feature: their elucidation requires two very different approaches that are provided by two scientific fields, epidemiology and basic science. Identifying the causes of illness is of interest for public health interventionists because the assumption is that illness can be prevented by eliminating such factors from populations. In order to prevent illness, epidemiological work is geared toward finding preventable risk factors. Epidemiologists approach the issue of causal inference by searching for risk factors that can be considered candidate causes. One main technique for causal inference described in epidemiology textbooks is based on a paper published in the mid-1960s.
