Table 2.
Subject characteristics by change in mammographic BI-RADS breast density from 1st to 2nd mammographic screening
| Characteristics | Change in BI-RADS breast density category
|
||
|---|---|---|---|
| No change (n = 12,020) | Decrease of ≥1 category (n = 3,153) | Increase of ≥1 category (n = 2,974) | |
| Age at 1st screen, mean (SD), y | 62.6 (8.5) | 62.7 (8.6) | 63.6 (8.5) |
| BMI at 1st screen, mean (SD), kg/m2 | 27.8 (6.3) | 27.5 (6.0) | 28.4 (7.5) |
| Race | |||
| White | 91.8 | 91.2 | 92.0 |
| Black | 2.5 | 2.7 | 2.5 |
| Asian/Pacific Islander | 4.8 | 5.3 | 4.9 |
| Other/unknown | 0.8 | 0.8 | 0.7 |
| Unit change in body mass index, (kg/m2) | |||
| No change | 57.1 | 59.1 | 54.6 |
| Decrease of ≥1 units | 19.4 | 17.1 | 22.6 |
| Increase of ≥1 units | 23.5 | 23.8 | 22.9 |
| Family history of breast cancer | 39.2 | 40.4 | 38.1 |
| Parous | 85.4 | 85.4 | 85.7 |
| Age at menopause, y | |||
| <30 | 6.2 | 6.0 | 4.6 |
| 30–39 | 11.3 | 12.3 | 11.7 |
| 40–49 | 37.9 | 36.6 | 38.7 |
| 50–59 | 43.8 | 44.0 | 44.3 |
| ≥60 | 0.8 | 1.1 | 0.8 |
| Hormone use | |||
| Never user | 41.5 | 42.3 | 43.0 |
| Discontinuer | 7.8 | 9.8 | 6.6 |
| Initiator | 4.0 | 3.1 | 4.3 |
| Continuer | 46.7 | 44.8 | 46.1 |
| BI-RADS breast density category at 1st screen | |||
| Almost entirely fat | 5.7 | 0.0 | 26.4 |
| Scattered fibroglandular tissue | 44.8 | 22.1 | 58.4 |
| Heterogeneously dense | 44.9 | 55.8 | 15.2 |
| Extremely dense | 4.6 | 22.1 | 0.0 |
| Statin use at 2nd screen* | |||
| Nonuser | 91.7 | 91.7 | 90.6 |
| Discontinuer | 0.4 | 0.5 | 0.6 |
| Initiator | 2.5 | 2.3 | 2.6 |
| Continuer | 5.4 | 5.5 | 6.2 |
*
We defined nonusers as women who were not using statins at either screen, discontinuers as users of statins at the 1st screen but nonusers at the 2nd screen, initiators as nonusers of statins at the 1st screen but users of statins at the 2nd screen, and continuers as users of statins at both screens.