Table 3 The relationships between Cirrus and mammographic density measures analysed by using the ICE FALCON method

Light areas–bright areas

Self

0.802 (0.030)

2 × 10^–161

0.770 (0.033)

5 × 10^–117

0.032 (0.013)

2 × 10^–2

Yes (11%)

Light areas cause bright areas (89%)

Co-twin

0.513 (0.041)

4 × 10^–35

0.070 (0.027)

10^–2

0.443 (0.037)

8 × 10^–34

Bright areas–light areas

Self

0.770 (0.025)

4 × 10^–210

0.727 (0.026)

10 × 10^–174

0.043 (0.011)

5 × 10^–5

Yes (42%)

Bright areas cause light areas (58%)

Co-twin

0.404 (0.045)

10^–19

0.144 (0.025)

8 × 10^–9

0.259 (0.035)

10^–13

Light areas–Cirrus

Self

0.352 (0.041)

6 × 10^–18

0.328 (0.041)

3 × 10^–15

0.024 (0.011)

2 × 10^–2

Yes (63%)

Light areas cause Cirrus (37%)

Co-twin

0.176 (0.038)

4 × 10^–06

0.087 (0.037)

0.02

0.089 (0.020)

10^–5

Cirrus–light areas

Self

0.285 (0.035)

2 × 10^–16

0.303 (0.034)

6 × 10^–19

 − 0.018 (0.008)

2 × 10^–2

Co-twin

0.091 (0.033)

6 × 10^–03

0.135 (0.030)

9 × 10^–6

 − 0.045 (0.015)

3 × 10^–3

Bright areas–Cirrus

Self

0.398 (0.038)

6 × 10^–26

0.367 (0.039)

2 × 10^–21

0.031 (0.010)

2 × 10^–3

Yes (72%)

Bright areas cause Cirrus (28%)

Co-twin

0.215 (0.038)

10^–08

0.139 (0.036)

10^–4

0.076 (0.021)

2 × 10^–4

Cirrus–bright areas

Self

0.361 (0.034)

5 × 10^–26

0.355 (0.034)

10^–25

0.006 (0.008)

0.5

Co-twin

0.165 (0.036)

6 × 10^–06

0.163 (0.033)

7 × 10^–7

0.002 (0.017)

0.9

Brightest areas (Cirrocumulus)–Cirrus

Self

0.351 (0.040)

2 × 10^–18

0.356 (0.039)

2 × 10^–20

 − 0.005 (0.008)

0.5

Yes (66%)

Cirrus causes brightest areas (Cirrocumulus) (34%)

Co-twin

0.138 (0.035)

9 × 10^–05

0.166 (0.032)

3 × 10^–7

 − 0.028 (0.016)

8 × 10^–2

Cirrus–brightest areas (Cirrocumulus)

Self

0.389 (0.039)

10^–23

0.360 (0.040)

9 × 10^–20

0.028 (0.010)

4 × 10^–3

Co-twin

0.191 (0.038)

5 × 10^–07

0.114 (0.036)

2 × 10^–03

0.077 (0.018)

3 × 10^–5

Light areas–brightest areas (Cirrocumulus)

Self

0.470 (0.036)

5 × 10^–38

0.424 (0.041)

3 × 10^–25

0.046 (0.017)

8 × 10^–3

Yes (45%)

Light areas cause brightest areas (Cirrocumulus)

(55%)

Co-twin

0.284 (0.040)

2 × 10^–12

0.103 (0.037)

5 × 10^–3

0.181 (0.025)

9 × 10^–13

Brightest areas (Cirrocumulus)–light areas

Self

0.347(0.035)

7 × 10^–23

0.395 (0.033)

4 × 10^–33

 − 0.048 (0.012)

6 × 10^–5

Co-twin

0.113 (0.034)

8 × 10^–4

0.221 (0.030)

10^–13

 − 0.108 (0.018)

3 × 10^–9

Bright areas–brightest areas (Cirrocumulus)

Self

0.680 (0.025)

10^–159

0.653 (0.029)

3 × 10^–109

0.027 (0.014)

6 × 10^–2

Yes (15%)

Bright areas cause brightest areas (Cirrocumulus)

(85%)

Co-twin

0.378 (0.039)

2 × 10^–22

0.058 (0.031)

7 × 10^–2

0.320 (0.031)

5 × 10^–25

Brightest areas (Cirrocumulus)–bright areas

Self

0.619 (0.032)

2 × 10^–84

0.606 (0.029)

4 × 10^–94

0.012 (0.010)

0.2

Co-twin

0.136 (0.038)

4 × 10^–4

0.202 (0.027)

8 × 10^–14

 − 0.065 (0.027)

2 × 10^–2

Light areas^a–brightest areas (Cirrocumulus)^a

Self

0.386 (0.038)

9 × 10^–25

0.365 (0.041)

6 × 10^–9

0.020 (0.016)

0.2

Yes (36%)

Light areas cause brightest areas (Cirrocumulus) not through Cirrus (64%)

Co-twin

0.198(0.043)

5 × 10^–6

0.051 (0.040)

0.2

0.147 (0.024)

5 × 10^–10

Brightest areas (Cirrocumulus)^a–light areas^a

Self

0.287 (0.034)

10^–17

0.339 (0.034)

2 × 10^–23

 − 0.052 (0.012)

2 × 10^–5

Co-twin

0.046 (0.036)

0.2

0.165 (0.033)

8 × 10^–7

 − 0.119(0.018)

7 × 10^–11

Bright areas ^a–brightest areas (Cirrocumulus)^a

Self

0.608(0.030)

4 × 10^–90

0.597 (0.033)

3 × 10^–75

0.011 (0.011)

0.3

Yes (8%)

Bright areas cause brightest areas (Cirrocumulus) not through Cirrus (92%)

Co-twin

0.268(0.044)

2 × 10^–9

0.033 (0.033)

0.3

0.234 (0.032)

2 × 10^–13

Brightest areas (Cirrocumulus) ^a–bright areas^a

Self

0.562(0.032)

6 × 10^–69

0.569 (0.031)

3 × 10^–77

 − 0.008 (0.008)

0.3

Co-twin

0.058 (0.044)

0.2

0.153 (0.031)

9 × 10^–7

 − 0.096 (0.028)

10^–3