Table 2.

Reliability of measures of mammographic features in the threshold and SMF methods and resulting attenuations of relative risk estimates

Mammographic feature (definition and units as per Table 1)Reliability coefficient
Attenuated RR (original RR, 4)*
Single filmLeft-right meanSingle filmLeft-right meanSingle filmLeft-right meanSingle filmLeft-right mean
CC views
    Breast size0.960.980.950.97
    Dense tissue0.890.940.910.95
    Nondense tissue0.960.980.940.97
    Percent density including edge0.920.960.770.873.583.782.913.34
    Percent density excluding edge0.790.882.993.39
MLO views
    Breast size0.960.980.940.97
    Dense tissue0.860.930.870.93
    Nondense tissue0.960.980.930.97
    Percent density including edge0.890.940.680.813.433.682.573.07
    Percent density excluding edge0.680.812.573.07
CC and MLO (average of four films)
    Percent density including edge0.970.873.843.34
    Percent density excluding edge0.883.39
  • Abbreviation: RR, relative risk.

  • * Attenuated relative risk (true relative risk, 4) of associations with density as an exposure, assuming nondifferential measurement error.