Table 2.

Crude and adjusted associations between tumor characteristics and breast density

Fatty (n = 373), %Dense (n = 173), %Crude analyses, OR* (95% CI)Adjusted analyses, OR (95% CI)
Tumor size (cm)
    0.1-1.039.728.01 (reference)1 (reference)
    1.1-2.043.047.61.6 (1.0-2.4)§2.0 (1.2-3.4)§
    2.1-1017.324.42.0 (1.2-3.3)§2.3 (1.3-4.4)§
    Missing (n)159
    P for trend0.0070.003
Lymph node status
    Negative78.167.51 (reference)1 (reference)
    Positive21.932.51.7 (1.1-2.6)§1.7 (1.0-2.8)§
    Missing (n)6319
Lymphatic or vascular invasion
    No90.080.51 (reference)1 (reference)
    Yes10.019.52.2 (1.3-3.8)§2.1 (1.0-4.2)§
    Missing (n)6219
Histologic grade
    Low37.844.51 (reference)1 (reference)
    Intermediate42.032.90.7 (0.4-1.0)0.9 (0.5-1.4)
    High20.222.61.0 (0.6-1.6)0.8 (0.4-1.5)
    Missing (n)6118
    P for trend0.560.47
Nuclear grade
    Low22.723.21 (reference)1 (reference)
    Intermediate51.150.31.0 (0.6-1.6)0.9 (0.5-1.7)
    High26.226.51.0(0.6-1.7)0.7 (0.4-1.4)
    Missing (n)6018
    P for trend0.970.33
Differentiation
    Low15.116.81 (reference)1 (reference)
    Intermediate26.328.41.0 (0.5-1.8)0.8 (0.4-1.6)
    High58.754.80.8 (0.5-1.4)0.9 (0.4-1.8)
    Missing (n)6118
    P for trend0.450.93
Mitoses
    Low67.061.31 (reference)1 (reference)
    Intermediate18.922.61.3 (0.8-2.1)1.1 (0.6-1.9)
    High14.116.11.3 (0.7-2.2)0.8 (0.4-1.7)
    Missing (n)6118
    P for trend0.290.69
Ki-67 (%)
    <2531.129.21 (reference)1 (reference)
    25-10068.970.81.1 (0.7-1.7)1.0 (0.6-1.7)
    Missing (n)6819
Tumor necrosis
    None63.662.61 (reference)1 (reference)
    Low27.529.01.1 (0.7-1.7)1.0 (0.6-1.7)
    Intermediate/high8.98.41.0 (0.5-1.9)0.9 (0.4-2.2)
    Missing (n)6018
    P for trend0.950.88
Estrogen receptor
    Positive84.181.31 (reference)1 (reference)
    Negative15.918.71.2 (0.7-2.0)1.1 (0.6-2.0)
    Missing (n)6418
Progesterone receptor
    Positive76.371.01 (reference)1 (reference)
    Negative23.729.01.3 (0.9-2.0)1.5 (0.9-2.6)
    Missing (n)6518
p53
    ≤10% Positive87.489.01 (reference)1 (reference)
    >10% Positive12.611.00.9 (0.5-1.6)0.7 (0.3-1.4)
    Missing (n)7118
p27
    Medium/high49.449.71 (reference)1 (reference)
    Negative/low50.650.31 (0.7-1.5)0.8 (0.5-1.3)
    Missing (n)6518
Cyclin E
    Low/medium93.294.21 (reference)1 (reference)
    High6.85.80.8 (0.4-1.9)0.6 (0.2-1.6)
    Missing (n)6519
Bcl-2
    Medium/high49.754.81 (reference)1 (reference)
    Negative/low50.345.20.8 (0.6-1.2)0.9 (0.5-1.4)
    Missing (n)6518
C-erb-B2
    Negative/low83.381.91 (reference)1 (reference)
    Medium/high16.718.11.1 (0.7-1.8)1.2 (0.6-2.2)
    Missing (n)6718
  • * For dense breasts compared with fatty breasts.

  • Adjusted for BMI, age at diagnosis, menopausal status/age at menopause, age at first birth, and AJCC stage.

  • Tumor size and lymph node status were not adjusted for stage.

  • § P < 0.05.