Table 3.
Five-year risk of incident epithelial ovarian cancer: adjusted hazard ratio (HR) and 95% confidence interval (CI) associated with Breast Imaging Reporting and Data System breast density category, overall and stratified by age group
| Breast density | No. of ovarian cancer cases* | HR† (95% CI) |
|---|---|---|
| All ages‡ | 1022 | |
| Almost entirely fat | 150 | 0.99 (0.82 to 1.20) |
| Scattered | 565 | 1.00 (referent) |
| Heterogeneous | 507 | 1.20 (1.06 to 1.36) |
| Extremely dense | 116 | 1.18 (0.93 to 1.50) |
| P trend§ | .01 | |
| Aged 40–49 y‡ | 207 | |
| Almost entirely fat | 10 | 1.04 (0.52 to 2.08) |
| Scattered | 73 | 1.00 (referent) |
| Heterogeneous | 120 | 1.30 (0.97 to 1.74) |
| Extremely dense | 38 | 1.22 (0.78 to 1.91) |
| P trend§ | .23 | |
| Aged 50–59 y‡ | 314 | |
| Almost entirely fat | 37 | 1.11 (0.76 to 1.62) |
| Scattered | 146 | 1.00 (referent) |
| Heterogeneous | 160 | 1.30 (1.03 to 1.64) |
| Extremely dense | 47 | 1.65 (1.12 to 2.44) |
| P trend§ | .02 | |
| Aged 60–69 y | 335 | |
| Almost entirely fat | 59 | 1.03 (0.77 to 1.40) |
| Scattered | 188 | 1.00 (referent) |
| Heterogeneous | 161 | 1.33 (1.06 to 1.67) |
| Extremely dense | 19 | 0.79 (0.47 to 1.33) |
| P trend§ | .19 | |
| Aged 70–79 y | 290 | |
| Almost entirely fat | 55 | 0.89 (0.65 to 1.21) |
| Scattered | 197 | 1.00 (referent) |
| Heterogeneous | 114 | 0.96 (0.76 to 1.20) |
| Extremely dense | 16 | 0.99 (0.54 to 1.83) |
| P trend§ | .82 |
* The number of case patients by density and age group sum to more than the total number of case patients because women with multiple mammograms can appear in multiple density and age groups.
† Hazard ratio, stratified by Breast Cancer Surveillance Consortium registry and adjusted for age, oral contraceptive use, hormone therapy use, parity status, prior diagnosis of breast cancer, and family history of breast or ovarian cancer in a first-degree relative.
‡ Additionally adjusted for postmenopausal status.
§ Two-sided Wald test.