Table 1.

Distribution of density and/or breast cancer risk factors in study population

Mean (SD)Range
Age at examination, y56.4 (4.16)49.2-65.8
Weight, kg67.7 (9.83)43.5-105.0
Height, m1.63 (0.06)1.46-1.87
BMI, kg/m225.6 (3.41)17.8-42.8
Age at menarche,* y13.5 (1.57)11.0-18.3
Age at menopause, y49.6 (3.78)32.0-60.0
Time since menopause, y7.5 (5.36)0.1-28.5
Parity (no. children)2.4 (1.91)0-9
Age at first childbirth, y27.3 (4.11)18.1-39.9
n (proportion)
Parous (yes)332 (79%)
Current oral contraceptive use (yes)8 (2%)
Ever used oral contraceptives (yes)43 (10%)
Used hormone therapy in the last 12 mo (yes)47 (11%)
Ever smoked (yes)116 (28%)
Family history of breast cancer (yes)§26 (6%)
Median (interquartile range)
Range
Breast size, cm2123.7 (94.7-162.6)29.1-345.3
Absolute amount dense tissue, cm226.4 (15.2-46.4)0.3-138.0
Absolute amount nondense tissue, cm287.855.6-130.6
Percent dense23.211.6-43.6
  • * Data available for 416 women.

  • Data available for 361 women.

  • Including only parous women; n = 332.

  • § Data available for 408 women.