Table 3.
Hazard ratios per SD of breast density assessments and breast cancer risk, by time since mammogram
| Density measure | ≤ 2 years | > 2 to 5 years | > 5 to 10 years | |||
|---|---|---|---|---|---|---|
| HRa | 95% CI | HRa | 95% CI | HRa | 95% CI | |
| LIBRA (MLOb only) | ||||||
| Dense area (DA) | 1.34 | 1.12–1.61 | 1.42 | 1.25–1.61 | 1.40 | 1.19–1.65 |
| Non-dense area (NDA) | 0.92 | 0.78–1.08 | 0.87 | 0.73–1.03 | 0.79 | 0.66–0.93 |
| Percent density (PD) | 1.37 | 1.08–1.75 | 1.45 | 1.25–1.69 | 1.54 | 1.33–1.79 |
| LIBRA (CCb only) | ||||||
| Dense area (DA) | 1.27 | 1.12–1.43 | 1.32 | 1.16–1.50 | 1.26 | 1.11–1.42 |
| Non-dense area (NDA) | 0.97 | 0.82–1.13 | 0.87 | 0.74–1.04 | 0.79 | 0.67–0.93 |
| Percent density (PD) | 1.30 | 1.12–1.52 | 1.35 | 1.16–1.57 | 1.38 | 1.19–1.60 |
| Cumulus | ||||||
| Dense area (DA) | 1.44 | 1.26–1.63 | 1.43 | 1.25–1.62 | 1.48 | 1.31–1.68 |
| Non-dense area (NDA) | 0.86 | 0.73–1.01 | 0.88 | 0.74–1.05 | 0.72 | 0.61–0.86 |
| Percent density (PD) | 1.55 | 1.25–1.91 | 1.46 | 1.25–1.71 | 1.67 | 1.43–1.96 |
Number of breast cancers for ≤ 2 years, > 2 to 5 years and > 5 to 10 years were 322, 290 and 315, respectively. LIBRA and Cumulus DA and PD were log-transformed, and LIBRA and Cumulus NDA were untransformed
aHazard ratios adjusted for age at FFDM (spline), mammogram year (categorical), BMI (spline), parity, first-degree family history, and HRT use within 5 years prior to mammogram date. Cumulus analyses were also adjusted for image batch. HRs are per standard deviation of density based on distribution in full cohort. Meta-analysis was used to combine Hologic and GE results
bAverage of measures on right and left breasts