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Table 3 Adjusted mean mammographic density measures according to reproductive and hormonal exposures among postmenopausal women

From: Predictors of mammographic density among women with a strong family history of breast cancer

  

Postmenopausal women (n = 59)

 

Percent Density (%)

 

Dense Area (cm2)

 

Non-Dense Area (cm2)

n

Mean1 PD

95% CI1

P 1

n

Mean1 DA

95% CI1

P 1

n

Mean1 NDA

95% CI1

P 1

Age at menarche

 <13 years

21

14.3

8.7-21.2

 

18

18.0

10.8-27.0

 

18

121.6

92.3-154.9

 

 ≥13 years

38

13.8

8.6-20.2

0.85

37

21.7

14.2-30.8

0.36

37

133.0

104.3-165.3

0.44

Parity

 Nulliparous

13

17.4

10.3-26.2

 

11

24.9

15.1-37.1

 

11

120.0

86.8-158.6

 

 Parous

46

13.5

8.6-19.4

0.24

44

19.4

12.7-27.5

0.25

44

128.1

101.4-158.0

0.63

Total live births2

 1

6

21.3

11.7-33.8

ref

6

29.4

17.8-44.0

ref

6

95.1

59.5-139.1

ref

 2

22

12.9

7.0-20.4

0.09

20

19.5

12.0-28.9

0.11

20

143.0

106.9-184.3

0.04

 ≥3

18

12.8

6.4-21.5

0.11

18

20.9

12.3-31.6

0.19

18

146.4

106.4-192.9

0.04

Breastfeeding2

 Never

10

14.1

6.3-25.0

 

10

26.4

15.2-40.6

 

10

154.9

106.5-212.4

 

 Ever

35

14.2

8.3-21.8

0.97

34

20.9

13.5-29.8

0.29

34

129.6

97.0-166.8

0.25

Breastfeeding duration2

 <11 months

26

12.9

6.9-20.8

 

24

20.9

12.8-31.1

 

24

148.8

110.8-192.5

 

 ≥11 months

20

15.8

8.9-24.7

0.41

20

22.7

14.2-33.3

0.69

20

119.8

85.8-159.4

0.12

OC use

 Never

5

9.0

2.6-19.3

 

4

16.4

5.5-33.2

 

4

149.4

94.9-216.2

 

 Ever

53

13.9

9.2-19.7

0.24

50

20.1

13.4-28.1

0.59

50

128.9

103.3-157.3

0.45

Duration of OC use

 <9 years

26

14.6

9.0-21.5

 

26

19.9

12.4-29.2

 

26

120.5

93.5-151.0

 

 ≥9 years

27

12.9

7.6-19.6

0.55

24

20.1

12.3-29.8

0.95

24

140.6

110.3-174.6

0.16

HRT use

 Never

43

13.7

8.7-19.7

ref

39

19.9

13.1-28.1

ref

39

133.0

106.5-162.5

ref

 Former

9

14.8

7.2-25.0

0.77

9

19.1

9.4-32.1

0.88

9

100.4

66.3-141.5

0.08

 Current

7

16.1

7.4-28.2

0.60

7

24.0

11.7-40.8

0.52

7

123.8

80.7-176.1

0.68

  1. 1Adjusted least-square means, 95% confidence intervals, and P-values are from analyses using square root-transformed mammographic density measures. The adjusted least-square means and 95% confidence intervals were back-transformed
  2. 2Among parous women only
  3. All models were adjusted for age (continuous) and BMI (continuous) at the time of mammogram, parity (continuous), and mammogram modality (digital image, film scanned by study team, film scanned by imaging centre).The parity (total live births) and breastfeeding models were additionally adjusted for age at first birth (continuous). OC, oral contraceptives. HRT, hormone replacement therapy
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BMC Cancer

ISSN: 1471-2407

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