ATTRIBUTABLE RISK - ADVANTAGES OF A BROAD DEFINITION OF EXPOSURE

Classification of exposure into two levels-one consisting exclusively of unexposed individuals and the other consisting of exposed and perha ps unexposed ones-yields an unbiased estimate of attributable risk whe n misclassification is nondifferential. The authors advocate, therefor e, the use of a broad definition of exposure when estimating attributa ble risk. Based on this idea, they justify a simple and robust method for estimating the overall attributable risk from several exposures th at is based on a division of subjects into two groups, a baseline cons isting of those unexposed to all exposures and everyone else.