Table 3.
Odds ratios (OR) and 95 % confidence intervals (CI) for breast cancer risk associated with BI-RADS measured mammographic density by age, body mass index (BMI), and hormone therapy (HT) use
| BI-RADS categorized density | Cases | Controls | Age and race adjusted OR (95 % CI)a |
Model 2 OR (95 % CI)b |
|---|---|---|---|---|
| All women | ||||
| Entirely fat | 13 | 25 | 0.46 (0.22–0.96) | 0.48 (0.22–1.08) |
| Scattered fibroglandular densities | 183 | 197 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 232 | 253 | 0.97 (0.72–1.29) | 1.00 (0.73–1.35) |
| Extremely dense | 63 | 53 | 1.13 (0.71–1.78) | 1.19 (0.72–1.95) |
| Ptrend = 0.24c | Ptrend = 0.24c | |||
| Current hormone therapy | ||||
| Yes | ||||
| Entirely fat | 3 | 8 | 0.58 (0.14–2.46) | 0.46 (0.08–2.53) |
| Scattered fibroglandular densities | 39 | 69 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 70 | 97 | 1.25 (0.73–2.14) | 1.13 (0.64–2.00) |
| Extremely dense | 17 | 7 | 5.09 (1.83–14.16) | 5.61 (1.86–16.96) |
| Ptrend = 0.005 | Ptrend = 0.01 | |||
| No | ||||
| Entirely fat | 10 | 17 | 0.41 (0.17–0.97) | 0.49 (0.19–1.26) |
| Scattered fibroglandular densities | 142 | 124 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 161 | 151 | 0.91 (0.64–1.30) | 0.93 (0.64–1.34) |
| Extremely dense | 46 | 44 | 0.72 (0.42–1.22) | 0.80 (0.45–1.43) |
| Prend = 0.82 | Prend = 0.88 | |||
| Test of effect modification by HT P = 0.0002 | ||||
| Age | ||||
| <50 | ||||
| Entirely fat | 4 | 4 | 0.93 (0.20–4.20) | 0.78 (0.16–3.77) |
| Scattered fibroglandular densities | 56 | 66 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 110 | 114 | 1.14 (0.71–1.81) | 1.10 (0.68–1.79) |
| Extremely dense | 46 | 35 | 1.30 (0.71–2.39) | 1.45 (0.75–2.79) |
| Prend = 0.38 | Prend = 0.27 | |||
| 50+ | ||||
| Entirely fat | 9 | 21 | 0.36 (0.15–0.87) | 0.40 (0.15–1.04) |
| Scattered fibroglandular densities | 127 | 131 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 122 | 139 | 0.84 (0.58–1.22) | 0.92 (0.62–1.38) |
| Extremely dense | 17 | 18 | 0.88 (0.41–1.89) | 1.06 (0.46–2.40) |
| Ptrend = 0.67 | Ptrend = 0.46 | |||
| Test of effect modification by age P = 0.67 | ||||
| Body Mass Index | ||||
| Women with BMI < 25 | ||||
| Entirely fat | 1 | 5 | 0.11 (0.01–1.16) | 0.12 (0.01–1.36) |
| Scattered fibroglandular densities | 55 | 37 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 91 | 97 | 0.66 (0.38–1.14) | 0.67 (0.38–1.19) |
| Extremely dense | 36 | 30 | 0.70 (0.34–1.42) | 0.75 (0.36–1.57) |
| Ptrend = 0.64 | Ptrend = 0.74 | |||
| Women with BMI 25–29 | ||||
| Entirely fat | 5 | 5 | 0.99 (0.25–3.95) | 1.36 (0.28–6.55) |
| Scattered fibroglandular densities | 49 | 64 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 71 | 87 | 1.01 (0.60–1.70) | 1.24 (0.70–2.20) |
| Extremely dense | 16 | 17 | 1.14 (0.49–2.66) | 1.35 (0.52–3.49) |
| Prend = 0.82 | Prend = 0.52 | |||
| Women with BMI 30+ | ||||
| Entirely fat | 7 | 15 | 0.45 (0.15–1.36) | 0.43 (0.15–1.28) |
| Scattered fibroglandular densities | 79 | 96 | 1.00 (referent) | 1.00 (referent) |
| Heterogeneously dense | 70 | 69 | 1.16 (0.72–1.87) | 1.24 (0.76–2.04) |
| Extremely dense | 11 | 6 | 2.52 (0.86–7.38) | 3.29 (1.00–10.83) |
| Ptrend= 0.03 | Ptrend= 0.01 | |||
| Test of effect modification by BMI P = 0.09 | ||||
BI-RADS Breast Imaging Reporting and Data System
a
Adjusted for matching factors, age and race
b
Model 2 is adjusted for age, race, BMI, menopausal status, family history of breast cancer, age at menarche, HT, and parity and age at first full-term pregnancy combined, where BI-RADS category 2 (scattered ribroglandular densities) is the referent group
c
P for trend test is based on likelihood ratio test statistic and is two-sided