Table 2.
Odds ratios (OR) and 95 % confidence intervals (CI) for breast cancer risk associated with BI-RADS measured mammographic density by race
| BI-RADS categorized density | Cases | Controls | Age and race adjusted OR (95 % CI) a |
Model 1 OR (95 % CI)b |
Model 2 OR (95 % CI)c |
|---|---|---|---|---|---|
| All women | |||||
| Entirely fat | 13 | 25 | 0.46 (0.22–0.96) | 1.00 (referent) | 0.48 (0.22–1.08) |
| Scattered fibroglandular densities | 183 | 197 | 1.00 (referent) | 2.07 (0.93–4.59) | 1.00 (referent) |
| Heterogeneously dense | 232 | 253 | 0.97 (0.72–1.29) | 2.06 (0.92–4.60) | 1.00 (0.73–1.35) |
| Extremely dense | 63 | 53 | 1.13 (0.71–1.78) | 2.45 (0.99–6.09) | 1.19 (0.72–1.95) |
| Ptrend = 0.24d | Ptrend = 0.24e | ||||
| White women | |||||
| Entirely fat | 5 | 10 | 0.39 (0.12–1.26) | 1.00 (referent) | 0.37 (0.10–1.35) |
| Scattered fibroglandular densities | 98 | 108 | 1.00 (referent) | 2.68 (0.74–9.74) | 1.00 (referent) |
| Heterogeneously dense | 144 | 171 | 0.90 (0.62–1.31) | 2.50 (0.69–9.07) | 0.93 (0.63–1.39) |
| Extremely dense | 50 | 35 | 1.34 (0.77–2.36) | 3.72 (0.94–14.81) | 1.39 (0.75–2.55) |
| Ptrend = 0.24 | Ptrend = 0.23 | ||||
| African American women | |||||
| Entirely fat | 8 | 15 | 0.49 (0.19–1.29) | 1.00 (referent) | 0.49 (0.17–1.40) |
| Scattered fibroglandular densities | 85 | 89 | 1.00 (referent) | 2.03 (0.71–5.77) | 1.00 (referent) |
| Heterogeneously dense | 88 | 82 | 1.07 (0.68–1.67) | 2.07 (0.71–6.03) | 1.02 (0.63–1.66) |
| Extremely dense | 13 | 18 | 0.76 (0.33–1.72) | 1.53 (0.40–5.92) | 0.75 (0.30–1.91) |
| Ptrend = 0.59 | Ptrend = 0.72 | ||||
| Test of effect modification by race P = 0.76 | |||||
BI-RADS Breast Imaging Reporting and Data System
Adjusted for matching factors age and race. Models for all, African American, and white women were adjusted for age, and the model for all women was also adjusted for race
Model 1 for African American and white women is adjusted for age, BMI, menopausal status, family history of breast cancer, age at menarche, HT use, and parity and age at first full-term pregnancy combined, where BI-RADS category 1 (almost entirely fat) is the referent group. Model 1 is additionally adjusted for race in all women
Model 2 is adjusted for the same variables as Model 1 but BI-RADS category 2 (scattered fibroglandular densities) is the referent group
P for trend test is based on likelihood ratio test statistic and is two-sided
P the same ordinal model was fit to assess the p value of trend for Model 1 and Model 2