Attributable fractions: bias from broad definition of exposure

Epidemiology. 2001 Sep;12(5):518-20. doi: 10.1097/00001648-200109000-00010.


In certain special situations, simplification of an exposure measure into a dichotomy results in no bias from nondifferential misclassification when estimating the attributable fraction for "any exposure." This fact has led to recommendations to use a broad definition of exposure when estimating attributable fractions. I here review the assumptions underlying exposure simplification, focusing on the assumptions that the source and target populations have the same exposure distribution and that complete risk removal is possible. I argue that attributable fraction estimates based on dichotomization can be especially sensitive to violations of these assumptions, and hence misleading for projecting the impact of exposure reduction. I conclude that it is important to obtain and use detailed exposure and covariate information for attributable-fraction estimation.

Publication types

  • Review

MeSH terms

  • Bias*
  • Biometry
  • Child
  • Electromagnetic Fields / adverse effects*
  • Environmental Exposure*
  • Humans
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / epidemiology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / etiology*
  • Risk Assessment
  • Sweden / epidemiology
  • United States / epidemiology