Table 4 Multivariable models with Breast Imaging Reporting and Data System breast density, dense breast volume, or both, with and without adjustment for body mass index

 Almost entirely fat = a

0.74 (0.62–0.89)

0.77 (0.64–0.92)

0.65 (0.54–0.78)

0.69 (0.57–0.84)

 Scattered fibroglandular densities = b

1.00 (reference)

1.00 (reference)

1.00 (reference)

1.00 (reference)

 Heterogeneously dense = c

1.34 (1.16–1.55)

1.17 (1.01–1.36)

1.45 (1.25–1.68)

1.26 (1.07–1.48)

 Extremely dense = d

2.01 (1.61–2.51)

1.63 (1.30–2.05)

2.45 (1.93–3.09)

1.93 (1.50–2.48)

Dense breast volume, ml, per SD^c

1.34 (1.26–1.42)

1.26 (1.18–1.35)

1.33 (1.25–1.42)

1.20 (1.11–1.29)

C-statistic^d

0.614 (0.598–0.630)

0.623 (0.607–0.639)

0.627 (0.611–0.642)

0.634 (0.618–0.649)

0.630 (0.614–0.645)

0.639 (0.623–0.654)