Table 2 Determinants of breast composition during puberty. Crude and adjusted mixed-effect models. The Growth and Obesity Cohort Study (n = 1,442 breast DXA scans)

% Fibroglandular Volume

Tanner stage

6.04

4.35 ; 7.73

< 0.001

0.01

6.33

4.63 ; 8.03

< 0.001

0.47

Menarche at DXA (yes/no)

8.04

6.79 ; 9.29

< 0.001

0.01

9.74

8.31 ; 11.17

< 0.001

0.53

Time to menarche (days)

0.01

0.004 ; 0.006

< 0.001

0.04

0.01

0.01 ; 0.02

< 0.001

0.50

Age (years)

1.85

1.60 ; 2.11

< 0.001

0.03

1.62*

1.39 ; 1.85

< 0.001

0.44

BMI z-score at DXA

-10.17

-10.92 ; -9.43

< 0.001

0.44

-9.80#

-10.54 ; -9.06

< 0.001

0.44

Height z-score at DXA

-2.64

-3.55 ; -1.72

< 0.001

0.003

0.26

0.03 ; 0.49

0.027

0.44

Mother´s %FGV

0.46

0.17; 0.75

0.002

0.02

0.18

-0.03; 0.39

0.085

0.44

Absolute Fibroglandular Volume

Tanner stage

53.03

45.88 ; 60.18

< 0.001

0.25

30.60

23.02 ; 38.18

< 0.001

0.32

Menarche at DXA (yes/no)

55.90

50.06 ; 61.75

< 0.001

0.29

50.16

43.66 ; 56.66

< 0.001

0.30

Time to menarche (days)

0.08

0.08 ; 0.08

< 0.001

0.39

0.07

0.05 ; 0.08

< 0.001

0.42

Age (years)

25.69

24.01 ; 27.37

< 0.001

0.31

26.63*

24.98 ; 28.28

< 0.001

0.36

BMI z-score at DXA

6.66

2.46 ; 10.85

0.002

0.02

16.19#

12.56 ; 19.83

< 0.001

0.36

Height z-score at DXA

-8.06

-12.37 ; -3.76

< 0.001

0.02

2.69

-1.95 ; 7.34

0.256

0.37

Mother’s AFGV

-0.07

-0.27; 0.14

0.536

0.02

0.18

0.17

-0.004; 0.34

0.056

0.37