Table 4.

Standardized percent density and absolute density are adjusted for age at examination and BMI

Percent densityAbsolute density
ThresholdVolumetricThreshold, cm2Volumetric, cm3
β95% CIβ95% CIβ95% CIβ95% CI
Age at examinationaPer year−0.056−0.077 to −0.036−0.060−0.082 to −0.038−0.049−0.071 to −0.026−0.005−0.027 to 0.017
BMIbPer 2-kg/m2 increase−0.206−0.241 to −0.170−0.144−0.182 to −0.105−0.137−0.176 to −0.0970.1910.153 to 0.230
NulliparousYes0.137−0.072 to 0.3460.2600.038 to 0.4820.118−0.112 to 0.3480.073−0.152 to 0.297
PostmenopausalYes−0.201−0.389 to −0.012−0.133−0.334 to 0.069−0.223−0.430 to −0.016−0.043−0.246 to 0.160
Age at menarchePer year0.045−0.012 to 0.1020.013−0.049 to 0.0750.044−0.018 to 0.107−0.008−0.070 to 0.054
Age at menopausePer year0.016−0.008 to 0.0410.015−0.010 to 0.0400.0240.000 to 0.0480.0290.005 to 0.053
Age at first deliveryPer 2 year0.0450.004 to 0.0860.0520.009 to 0.0960.0500.005 to 0.0940.033−0.011 to 0.078
Ever HT useYes0.134−0.061 to 0.3290.193−0.016 to 0.4020.186−0.029 to 0.4000.2150.006 to 0.424
Ever pill useYes−0.095−0.362 to 0.172−0.221−0.507 to 0.064−0.106−0.073 to 0.028−0.068−0.355 to 0.220
Family historyYes0.101−0.132 to 0.3350.077−0.172 to 0.3270.111−0.146 to 0.3670.052−0.198 to 0.302

NOTE: β is the number of SD change in breast density.

  • aβage is adjusted for BMI.

  • bβBMI is adjusted for age.