Table 1 Selected characteristics of the 964 participants.

   Age at screening, y

61.4 (± 4.6)

   Age at menarche, y

13.3 (± 1.4)

   Age at first birth*, y

22.9 (± 3.7)

   Number of children*

2.9 (± 1.3)

   Education, y

9.8 (± 3.4)

   Age at menopause, y

48.6 (± 5.1)

   BMI, kg/m²

27.3 (± 4.8)

Frequency (%)

   Ever Oral Contraceptive use

51.1

   Parous

92.6

   Ever postmenopausal hormone therapy use

43.4

   Current postmenopausal hormone therapy use

26.0

   Past postmenopausal hormone therapy use

17.3

   Never postmenopausal hormone therapy use

56.6

   Breast cancer in first degree relative

8.3

Median

   Percent mammographic density, %

9.6 (0-69.2)

   Absolute mammographic density, cm²

14.8 (0-155.2)

   Non-dense mammographic area, cm²

147.0 (21.6-448.9)

   IGF1 (ng/ml)

28.7 (2.2-104.6)

   IGFBP3 (ng/ml)

151.2 (52.17-241.5)