Table 3.

% Breast density by circulating hormone quintile and results of multiple regression of square root of % dense on circulating hormone levels

Hormone or ratio (quintile cut points)*Mean % dense (95% CI)
Adjusted least square mean % dense (95% CI)
Regression results
Q2Q3Q4Q5Q1Q2Q3Q4Q5β coefficient (95% CI)PR2n
Estradiol (pmol/L; 11, 14, 18, 25)22.4 (19.7-25.3)23.9 (21.3-26.7)17.5 (15.4-19.8)16.2 (14.1-18.4)20.1 (18.2-22.2)20.8 (18.4-23.4)22.7 (20.3-25.1)19.5 (17.4-21.7)19.9 (17.7-22.4)0.0005 (−0.0081 to 0.0091)0.910.1881,413
Testosterone (nmol/L; 0.42, 0.60, 0.83, 1.17)23.0 (20.5-25.6)19.2 (16.9-21.6)19.5 (17.2-21.9)19.9 (17.5-22.4)20.0 (17.9-22.3)21.6 (19.3-23.9)19.3 (17.2-21.5)20.5 (18.4-22.8)21.4 (19.1-23.8)0.0523 (−0.1687 to 0.2732)0.640.1881,413
SHBG (nmol/L; 27.0, 36.0, 45.0, 60.2)19.3 (17.0-21.6)17.6 (15.4-19.9)22.5 (20.0-25.3)27.5 (24.8-30.4)20.6 (18.3-22.9)20.5 (18.4-22.7)17.6 (15.5-19.7)20.6 (18.4-22.9)23.4 (21.0-25.9)0.0044 (−0.0007 to 0.0095)0.090.1901,408
Androstenedione (nmol/L; 2.19, 2.89, 3.68, 4.83)21.7 (18.9-24.7)16.7 (14.2-19.4)22.2 (19.4-25.3)20.2 (17.5-23.0)20.8 (18.2-23.5)21.1 (18.5-23.8)17.2 (14.9-19.6)22.4 (19.7-25.2)20.8 (18.3-23.5)−0.0043 (−0.0734 to 0.0647)0.900.1901,010
17-OH-progesterone (nmol/L; 0.73, 0.94, 1.18, 1.56)18.9 (16.6-21.4)19.6 (17.3-22.1)21.9 (19.4-24.5)20.6 (18.2-23.2)20.9 (18.7-23.2)18.9 (16.8-21.1)19.1 (17.1-21.3)22.4 (20.1-24.9)21.2 (18.9-23.5)0.0592 (−0.1235 to 0.2420)0.530.1851,365
Estrone (pmol/L; 53.0, 70.0, 87.0, 116.4)22.8 (19.5-26.3)17.3 (14.5-20.5)20.8 (17.7-24.3)16.5 (13.8-19.5)20.7 (17.9-23.8)21.3 (18.5-24.4)17.6 (15.0-20.5)21.5 (18.6-24.6)19.2 (16.5-22.2)−0.0002 (−0.0039 to 0.0035)0.930.212807
Estrone sulfate (pmol/L; 399, 622, 902, 1,296)26.6 (20.4-33.7)13.3 (9.5-17.7)19.2 (14.3-25.0)17.8 (12.6-23.9)22.5 (17.1-28.6)24.2 (18.7-30.4)13.4 (9.4-18.0)21.1 (16.0-26.9)21.0 (15.8-27.0)0.0000 (−0.0004 to 0.0004)0.980.204259
Estradiol/testosterone ratio (/1,000; 15.0, 20.5, 26.3, 37.1)21.6 (19.2-24.1)19.7 (17.4-22.1)18.5 (16.2-21.0)19.5 (17.1-22.0)21.4 (19.2-23.8)20.8 (18.6-23.1)20.2 (18.1-22.4)19.6 (17.5-21.8)20.7 (18.5-23.0)(−0.0064 to 0.0039)0.620.1771,413
Estrone/androstenedione ratio (/1,000; 15.8, 21.7, 27.7, 38.1)21.8 (18.6-25.2)20.1 (16.9-23.7)20.5 (17.3-23.9)17.2 (14.4-20.2)19.3 (16.5-22.2)20.7 (17.9-23.8)20.2 (17.4-23.2)20.5 (17.7-23.5)19.8 (17.0-22.9)0.0025 (−0.0074 to 0.0123)0.620.212799
Estradiol/SHBG ratio (/1,000; 0.210, 0.328, 0.496, 0.762)22.7 (20.2-25.3)19.9 (17.6-22.3)18.7 (16.4-21.1)14.7 (12.9-16.7)23.0 (20.5-25.5)20.6 (18.4-22.9)19.4 (17.3-21.6)20.9 (18.7-23.2)18.9 (16.6-21.2)0.0022 (−0.2282 to 0.2325)0.990.1881,408
17-OH-progesterone/androstenedione ratio (0.220, 0.281, 0.341, 0.436)20.2 (17.5-23.0)21.7 (18.7-25.0)19.0 (16.3-21.9)20.8 (17.9-24.0)20.0 (17.4-22.7)21.0 (18.4-23.8)21.4 (18.8-24.2)18.9 (16.4-21.5)20.7 (18.1-23.4)0.2345 (−0.5920 to 1.0609)0.580.187988
  • * 20th, 40th, 60th, and 80th percentiles.

  • Based on mean of square root of % density for comparability with adjusted least square mean.

  • Obtained by linear regression model of square root of % dense, adjusting for sextile of BMI, parity (0, 1, 2, 3, 4+), cigarette smoking, years since menopause (<5, 5 to <10, 10-14, 15-19, 20+), and age at menarche (9-11, 12-13, 14+).