Attributable Fractions

The attributable fraction is one of a class of measures used by epidemiologists to quantify the impact of an exposure or intervention on the occurrence of a disease or other outcome events in a population. These measures can be used, for example, to examine the impact of obesity on disease risk and the potential or expected impact of weight-reduction programs on disease rates. The origin of this concept is a measure proposed by a cancer epidemiologist, Morton Levin, in 1953. In describing the association between cigarette smoking and lung cancer, Levin (1953) offers the following definition of the new measure:

• The third index (S) is the … maximum proportion of lung cancer attributable to smoking. This index is based on the assumption that smokers, if they ...