Table 3.
Relative risks of breast cancer within 3 years of a negative mammographic screening result in relation to use of hormone replacement therapy, family history of breast cancer, and mammographic features
| Study participant and mammographic features | HRa (95% CI) | HRb (95% CI) |
|---|---|---|
| Current use of HRT (same-year user vs. previous or nonuser) | 1.4 (0.9–2.1) | 1.3 (0.9–2.0) |
| Family history of breast cancer | 1.3 (1.1–1.7) | 1.3 (1.0–1.7) |
| Percentage mammographic density (cBIRADS 4 vs. 1) | 4.9 (2.8–8.6) | 4.8 (2.6–8.8) |
| Percentage mammographic density (per SD) | 1.6 (1.4–1.8) | 1.6 (1.4–1.8) |
| Number of microcalcificationsc (category 4 vs. 0) | 2.0 (1.3–3.1) | 2.0 (1.3–3.2) |
| Number of masses (4 vs. 0) | 1.7 (0.8–3.5) | 1.7 (0.8–3.5) |
| Individual absolute difference between breastsd | ||
| Percentage mammographic density | 3.4 (2.2–5.2) | 1.9 (1.2–3.0) |
| Number of microcalcifications | 2.5 (1.9–3.1) | 2.8 (1.8–4.5) |
| Number of masses | 1.4 (0.9–2.2) | 1.1 (0.6–1.9) |
HRT Hormone replacement therapy
aAdjusted for age, body mass index
bAdjusted for age, body mass index, mammographic density, microcalcifications, masses, breast cancer in family, menopausal status, and current use of HRT
cCategory 0 means 0 microcalcifications, and 1 is 1–10 microcalcifications. The corresponding numbers for 2, 3, and 4 are 11–20, 21–40, and >40 microcalcifications, respectively
dAbsolute difference between right and left breasts was calculated as the standard deviation SD of the breasts for each mammographic feature