Definitions of attributable risk--revisited

Abstract

Background: The concept of attributable risk is a popular approach to describe the disease risk associated with an exposure factor on the population level. The paper reviews this epidemiologic concept.

Methods: Definitions and interpretations of four measures of association term "attributable risk" in the epidemiologic literature are compared. By introducing the notation of exposure-specific disease events, the intrinsic relationship between these definitions in unveiled from a new perspective. In addition, the terminologic confusion relating to this concept is discussed.

Results: It is shown that all four definitions focus on the exposure-specific disease incidence, but all in different subpopulations of the study population. Data of a German cohort study on the relationship between lipoprotein fractions and myocardial infarction further illustrate the different measures of attributable risk.

Discussion: It is pointed out that the evaluation of the public health impact of an exposure under study by means of attributable risk calculations should form an integral part of the epidemiologic analysis.