Table 2 Distributions of quantitative tissue composition metrics according to characteristics of women volunteers who donated normal breast tissue to the US-based Susan G. Komen Tissue Bank that were included in the current study (N = 4108)

Overall

0.89 (0.0–70.4)

17.2 (0.0–95.7)

81.0 (0.0–100.0)

18.9 (0.0–97.2)

5.9 (0.0–100.0)

Age, years

 < 30

1.46 (0.0–25.1)

29.0 (0.0–93.5)

68.0 (5.1–100.0)

32.0 (0.0–94.9)

5.6 (0.0–85.2)

30–39

1.31 (0.0–53.4)

18.7 (0.0–92.2)

79.1 (6.1–100.0)

20.9 (0.0–93.9)

7.7 (0.0–98.7)

40–49

1.02 (0.0–70.4)

16.3 (0.0–91.8)

82.3 (7.3–100.0)

17.7 (0.0–92.7)

6.6 (0.0–100.0)

50–59

0.65 (0.0–18.4)

14.7 (0.0–91.3)

84.2 (6.4–100.0)

15.8 (0.0–93.6)

5.2 (0.0–100.0)

60–75

0.49 (0.0–13.0)

11.0 (0.0–95.8)

88.4 (2.8–100.0)

11.6 (0.0–97.2)

4.7 (0.0–93.8)

P value

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

Race/ethnicity

Non-Hispanic Caucasian

0.90 (0.0–53.4)

18.0 (0.0–95.8)

80.5 (2.8–100.0)

19.5 (0.0–97.2)

5.7 (0.0–100.0)

Black/African American

0.89 (0.0–70.4)

15.1 (0.0–88.9)

83.3 (6.1–100.0)

16.7 (0.0–93.9)

6.7 (0.0–92.2)

Asian/other

0.89 (0.0–25.1)

17.6 (0.0–91.8)

81.3 (6.1–100.0)

18.7 (0.0–93.9)

6.5 (0.0–92.9)

P value

0.98

0.02

0.08

0.08

0.01

Education

High school/GED or less

0.96 (0.0–70.4)

20.5 (0.0–93.3)

77.5 (5.1–100.0)

22.5 (0.0–94.9)

5.7 (0.0–100.0)

Vocation/tech school or associates degree

0.84 (0.0–21.3)

14.9 (0.0–95.8)

83.7 (2.8–100.0)

16.3 (0.0–97.2)

6.6 (0.0–100.0)

College degree

0.94 (0.0–26.6)

18.6 (0.0–92.7)

79.9 (5.7–100.0)

20.1 (0.0–94.3)

5.8 (0.0–93.7)

Graduate/professional degree

0.87 (0.0–53.4)

16.1 (0.0–93.1)

82.8 (6.4–100.0)

17.2 (0.0–93.6)

6.0 (0.0–98.7)

Other

0.85 (0.0–17.6)

17.3 (0.0–93.5)

80.8 (5.6–100.0)

19.2 (0.0–94.4)

5.7 (0.0–87.1)

P value

0.58

 < 0.0001

 < 0.0001

 < 0.0001

0.34

Smoking

Never

0.95 (0.0–53.4)

18.1 (0.0–95.8)

80.4 (2.8–100.0)

19.6 (0.0–97.2)

6.0 (0.0–100.0)

Former

0.72 (0.0–70.4)

15.7 (0.0–92.1)

83.3 (6.3–100.0)

16.7 (0.0–93.7)

5.3 (0.0–100.0)

Current

0.96 (0.0–9.76)

22.1 (0.0–92.5)

77.0 (5.7–100.0)

23.0 (0.0–94.8)

6.1 (0.0–93.7)

P value

0.008

0.13

0.02

0.02

0.03

Currently drink alcohol

No

0.86 (0.0–70.4)

15.3 (0.0–95.8)

83.2 (2.8–100.0)

16.8 (0.0–97.2)

6.3 (0.0–100.0)

Yes

0.92 (0.0–53.4)

18.4 (0.0–93.1)

80.2 (5.1–100.0)

19.8 (0.0–94.9)

5.8 (0.0–100.0)

P value

0.73

0.02

0.69

0.03

0.06

Average number of alcoholic drinks per week

 < 1

0.84 (0.0–23.3)

13.8 (0.0–84.6)

84.1 (10.5–100.0)

15.9 (0.0–89.5)

7.0 (0.2–93.7)

1–6

0.91 (0.0–53.4)

18.8 (0.0–93.1)

79.1 (5.1–100.0)

20.3 (0.0–95.9)

5.6 (0.0–100.0)

 ≥ 7

0.92 (0.0–15.4)

18.7 (0.0–91.9)

69.9 (6.9–100.0)

20.1 (0.0–93.0)

4.7 (0.0–62.4)

P value

0.69

0.003

0.006

0.006

 < 0.0001

Body mass index

 < 25

1.25 (0.0–53.4)

26.1 (0.0–95.8)

71.9 (2.8–100.0)

28.1 (0.0–97.2)

5.1 (0.0–98.7)

25–29

0.79 (0.0–36.2)

15.8 (0.0–93.5)

82.4 (5.6–100.0)

17.6 (0.0–94.4)

5.9 (0.0–100.0)

 ≥ 30

0.74 (0.0–70.4)

12.9 (0.0–92.4)

85.6 (6.1–100.0)

14.4 (0.0–93.9)

6.9 (0.0–97.5)

P value

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

Age at menarche, years

 ≤ 12

0.89 (0.0–70.4)

16.1 (0.0–92.7)

82.4 (5.1–100.0)

17.6 (0.0–94.9)

6.3 (0.0–100.0)

13

0.95 (0.0–53.4)

18.2 (0.0–95.8)

80.3 (2.8–100.0)

19.7 (0.0–97.2)

5.4 (0.0–89.7)

 ≥ 14

0.86 (0.0–24.9)

19.2 (0.0–93.1)

79.2 (5.2–100.0)

20.8 (0.0–94.8)

5.6 (0.0–100.0)

P value

0.54

0.009

0.01

0.01

0.002

Current hormonal birth control use

No

1.18 (0.0–70.4)

19.9 (0.0–93.5)

77.8 (5.1–100.0)

22.2 (0.0–94.9)

6.5 (0.0–100.0)

Yes

1.48 (0.0–24.7)

21.2 (0.0–92.7)

76.4 (6.3–99.9)

23.6 (0.0–93.7)

6.8 (0.0–85.2)

P value

0.10

0.29

0.28

0.28

0.29

Parity

Nulliparous

0.88 (0.0–25.1)

18.9 (0.0–93.5)

79.4 (5.1–100.0)

20.6 (0.0–94.9)

5.3 (0.0–100.0)

Parous

0.91 (0.0–70.4)

16.6 (0.0–95.8)

81.8 (2.8–100.0)

18.2 (0.0–97.2)

6.3 (0.0–100.0)

P value

0.44

0.13

0.06

0.06

 < 0.0001

Number of live births

0

0.74 (0.0–21.3)

21.2 (0.02–87.5)

76.7 (9.1–100.0)

23.3 (0.0–90.9)

5.3 (0.0–51.1)

1

0.91 (0.0–26.6)

16.8 (0.0–89.7)

81.8 (6.1–100.0)

18.2 (0.0–93.9)

5.8 (0.0–97.5)

2

0.98 (0.0–36.2)

15.6 (0.0–91.3)

82.5 (6.4–100.0)

17.5 (0.0 93.6)

6.7 (0.0–100.0)

 ≥ 3

0.87 (0.0–70.4)

15.0 (0.0–95.8)

83.6 (2.8–100.0)

16.4 (0.0–97.2)

6.9 (0.0–82.5)

P value

0.69

 < 0.0001

0.0003

0.0003

 < 0.0001

Age at first full-term birth, years

 < 25

0.83 (0.0–26.6)

15.0 (0.0–95.8)

84.1 (2.8–100.0)

15.9 (0.0–97.2)

6.3 (0.0–88.0)

25–29

1.06 (0.0–53.4)

18.7 (0.0–85.9)

79.9 (7.7–100.0)

20.1 (0.0–92.2)

5.9 (0.0–100.0)

 ≥ 30

1.08 (0.0–36.2)

17.2 (0.0–91.3)

81.2 (6.4–100.0)

18.8 (0.0–93.6)

5.7 (0.0–68.6)

P value

0.35

0.38

0.3612

0.36

0.0038

Breastfeeding

Never

0.68 (0.0–70.4)

13.5 (0.0–95.8)

85.6 (2.8–100.0)

14.4 (0.0–97.2)

6.2 (0.0–97.5)

Ever

1.05 (0.0–53.4)

17.5 (0.0–91.3)

80.9 (6.1–100.0)

19.1 (0.0–93.9)

6.6 (0.0–100.0)

P value

0.0002

 < 0.0001

 < 0.0001

 < 0.0001

0.0002

Breastfeeding duration, months

Never

0.7 (0.0–70.4)

13.5 (0.0–95.8)

85.6 (2.8–100.0)

14.4 (0.0–97.2)

6.2 (0.0–97.5)

 < 12

1.04 (0.0–26.6)

18.0 (0.0–91.3)

80.5 (6.1–100.0)

19.5 (0.0–93.9)

6.5 (0.0–100.0)

 ≥ 12– < 24

1.02 (0.0–36.2)

16.2 (0.0–89.3)

82.3 (8.6–100.0)

17.7 (0.0–91.4)

6.6 (0.0–65.9)

 ≥ 24

1.15 (0.0–53.4)

17.0 (0.0–90.5)

81.0 (7.7–100.0)

19.0 (0.0–92.2)

7.0 (0.0–91.0)

P value

0.0016

 < 0.0001

 < 0.0001

 < 0.0001

0.002

Bilateral oophorectomy

No

0.60 (0.0–18.4)

13.9 (0.0–90.6)

85.2 (9.2–100.0)

14.8 (0.0–90.8)

5.2 (0.0–93.7)

Yes

0.47 (0.0–12.0)

11.6 (0.0–79.3)

87.6 (20.4–100.0)

12.4 (0.0–79.6)

4.7 (0. 0–97.5)

P value

0.01

0.02

0.02

0.02

0.12

Menopausal status

Premenopausal

1.26 (0.0–70.4)

20.6 (0.0–93.5)

77.1 (5.1–100.0)

22.9 (0.0–94.9)

6.6 (0.0–100.0)

Postmenopausal

0.56 (0.0–21.3)

12.6 (0.0–95.8)

86.2 (2.8–100.0)

13.8 (0.0–97.2)

5.0 (0.0–100.0)

Uterine Ablation

1.07 (0.0–18.4)

20.6 (0.0–89.9)

77.5 (7.8–80.5)

22.5 (0.0–92.1)

7.6 (0.12–74.0)

P value

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

 < 0.0001

Menopausal hormone therapy

Nonuser

0.53 (0.0–18.4)

12.7 (0.0–91.3)

86.2 (6.4–100.0)

13.8 (0.0–93.6)

5.2 (0.0–100.0)

Current user

0.45 (0.0 10.0)

12.2 (0.0–95.8)

87.2 (2.7–100.0)

12.8 (0.0–97.2)

3.1 (0.0–87.1)

Former user

0.52 (0.0–13.0)

15.3 (0.0–90.6)

83.5 (9.3–100.0)

16.5 (0.0–90.7)

5.3 (0.0–55.9)

P value

0.0006

0.63

0.67

0.67

 < 0.0001

Menopausal hormone therapy type-current user

Nonuser

0.53 (0.0–18.4)

12.6 (0.0–91.3)

86.2 (6.4–100.0)

13.8 (0.0–93.6)

5.1 (0.0–100.0)

Estrogen only

0.60 (0.0–5.2)

11.0 (0.0–71.6)

88.7 (25.1–100.0)

11.3 (0.0–74.9)

4.0 (0.0–87.1)

Combined estrogen and progesterone

0.32 (0.0–9.1)

14.7 (0.1–86.7)

85.1 (12.2–99.9)

14.9 (0.1–87.8)

2.5 (0.0–57.6)

P value

0.04

0.54

0.61

0.61

 < 0.0001

Menopausal hormone therapy type-former user

Nonuser

0.53 (0.0–18.4)

12.6 (0.0–91.3)

86.2 (6.4–100.0)

13.8 (0.0–93.6)

5.1 (0.0–100.0)

Estrogen only

0.60 (0.0–6.3)

15.8 (0.02–68.4)

83.3 (30.5–100.0)

16.7 (0.0–69.5)

5.5 (0.0–42.7)

Combined estrogen and progesterone

0.51 (0.0–6.2)

9.8 (0.0–90.6)

89.7 (9.3–100.0)

10.3 (0.0–90.7)

4.2 (0.0–55.9)

P value

0.68

0.76

0.77

0.77

0.33

Family history of breast cancer

Negative

0.92 (0.0–53.4)

18.0 (0.0–95.8)

80.5 (2.8–100.0)

19.5 (0.0–97.2)

5.8 (0.0–100.0)

Positive

0.78 (0.0–70.4)

15.3 (0.0–93.3)

83.0 (5.3–100.0)

17.0 (0.0–94.7)

6. 2 (0.0–92.9)

P value

0.40

0.002

0.003

0.003

0.06