Table 2.

Association of demographic characteristics and breast cancer risk factors with mammographic density

BI-RADS 1 (n = 3,203)BI-RADS 2 (n = 19,932)BI-RADS 3 (n = 18,332)BI-RADS 4 (n = 3,344)P
Age, mean (SD)61.0 (12.1)56.1 (11.9)50.8 (10.9)46.8 (9.5)<0.001
Family history, first-degree relative (%)12.914.116.216.5<0.001
BMI, mean (SD)32.0 (7.9)28.6 (6.4)25.4 (4.8)22.7 (3.8)<0.001
HRT (%)19.921.327.125.5<0.001
Nulliparity (%)27.625.734.644.1<0.001
Premenopausal (%)35.040.243.643.8<0.001
Race (%)
White49.751.554.150.5
Asian10.715.82.833.9<0.001
Latina21.722.115.410.3<0.001
African American16.810.26.65.1<0.001
Native American0.40.20.10.040.001
  • NOTE: All variables are presented as age-adjusted proportions or means.