Table 2. Cross-sectional association between BMI and volumetric density measures at first mammogram; BCSC SFMR 2007-2013.
| N (women) | Mean (SD) at first mammogram | β (SE) a, b | 95% CI | P value | |
|---|---|---|---|---|---|
| All women | 24,556 | ||||
| Dense breast volume (cm3) | 142.3 (76.7) | 2.95 (0.13) | 2.69, 3.21 | < 0.001 | |
| Non-dense breast volume (cm3) | 416.8 (331.0) | 51.03 (0.56) | 49.93, 52.13 | < 0.001 | |
| Percent dense breast volume (%) | 32.5 (19.5) | -2.03 (0.03) | -2.09, -1.98 | < 0.001 | |
| Premenopausal at first mammogram | 8,355 | ||||
| Dense breast volume (cm3) | 166.7 (83.7) | 3.05 (0.27) | 2.51, 3.58 | < 0.001 | |
| Non-dense breast volume (cm3) | 327.1 (303.2) | 53.64 (0.98) | 51.72, 55.55 | < 0.001 | |
| Percent dense breast volume (%) | 42.3 (21.3) | -2.88 (0.06) | -3.00, -2.77 | < 0.001 | |
| Postmenopausal at first mammogram | 15,734 | ||||
| Dense breast volume (cm3) | 129.1 (69.1) | 2.97 (0.16) | 2.67, 3.28 | < 0.001 | |
| Non-dense breast volume (cm3) | 465.6 (336.2) | 49.96 (0.69) | 48.61, 51.31 | < 0.001 | |
| Percent dense breast volume (%) | 27.3 (16.2) | -1.67 (0.03) | -1.73, -1.61 | < 0.001 |
a
Adjusted for age at first mammogram, race, education, first degree family history of breast cancer, history of breast biopsy, ever given birth (yes/no), menopausal status at first mammogram (all women), and hormone use at first mammogram
b
Regression coefficient (β) represents the change in volumetric density measure associated with a 1 kg/m2 difference in BMI, holding the covariates above constant.
Stratified results exclude 467 women with unknown menopausal status at first mammogram
P value for interaction by menopausal status: p=0.79 for DV, p<0.01 for NDV, p<0.01 for PDV