The application of methods to quantify attributable risk in medical practice

Several epidemiological parameters have been introduced for quantifying the population impact of a certain exposure on morbidity on a population level , termed 'attributable risk' (AR). Of these definitions, the AR as suggeste d by Levin in 1953 or some algebraic transformations of it are most commonl y used. A structured literature search, based on the Medline database, iden tified 334 original epidemiological studies dealing with this AR published between 1966 and 1996 (mostly case-central studies). A considerable increas e in the number of published studies incorporating some quantification of t he exposure impact on the population level in terms of the AR was observed in the last decade. However, in 64.5% of these studies no exact definition of the AR used was given. Adjustment procedures necessary in multifactorial situations were performed by only 37.5%, confidence intervals for the AR w ere given by only 19.3% of authors. Thus, although the increasing popularit y of this important epidemiological measure is encouraging, its correct app lication and comprehensive reporting in medical practice should be promoted further.