Table 2.

Percent density: distribution of breast cancer risk factors by quintiles of threshold and volumetric methods

 Threshold method, percent densityVolumetric method, percent density
12345Ptrend12345Ptrend
(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)(N = 74)
Age at examination, y (mean)55.654.054.353.851.9<0.00156.254.154.053.052.4<0.001
BMI, kg/m2 (mean)29.326.425.724.022.3<0.00127.228.425.423.922.9<0.001
Age menarche, y (mean)12.713.113.512.913.50.0212.713.313.213.213.30.09
Nulliparous, %12.216.225.826.328.20.038.18.927.021.631.10.001
Number of children (median)1.81.81.51.81.60.191.91.71.71.81.40.04
Age first delivery,a y (mean)24.524.925.826.328.2<0.00124.424.926.126.528.1<0.001
Postmenopausal, %63.556.855.447.331.1<0.00166.258.150.044.635.1<0.001
Age menopause,b y (mean)47.949.347.149.048.90.6548.448.447.848.948.30.89
Ever HT use, %36.125.739.228.426.00.3139.226.429.728.431.50.43
Ever pill use, %87.791.990.583.889.20.6691.989.089.286.586.50.25
First-degree family history breast cancer, %13.521.618.913.514.90.6916.220.316.210.818.90.77
  • aParous women only.

  • bPostmenopausal women only.