From: Mammographic density, breast cancer risk and risk prediction
 | General population | Symptomatic population | |||||
---|---|---|---|---|---|---|---|
 | Incidence studies | Prevalence studies |  |  | |||
Classification | Cases/Non-casesa | RR (95% CI) | Cases/Non-casesa | RR (95% CI) | Cases/Non-casesa | RR (95% CI) | |
Wolfe parenchymal pattern | 2,664/23,469b | Â | Â | 2,169/32,184b | Â | 1,857/25,394b | Â |
   N1 | 181/3,613 | 1.0 | 557/15,731 | 1.0 | 428/3,318 | 1.0 | |
   P1 | 525/6,682 | 1.8 (1.4, 2.2) | 519/9,684 | 1.3 (1.0, 1.5) | 315/5,031 | 1.0 (0.77, 1.3) | |
   P2 | 1,162/10,433 | 3.1 (2.5, 3.7) | 660/4,369 | 2.0 (1.3, 3.0) | 526/5,128 | 1.5 (0.91, 2.4) | |
   DY | 246/2,309 | 4.0 (2.5, 6.3) | 294/2,216 | 2.4 (2.0, 3.0) | 400/4,976 | 1.7 (1.0, 2.8) | |
Percentage mammographic density | 4,508/8,342b | Â | Â | 2,219/4,063b | Â | 160/160b | Â |
   <5% | 1,194/1,744c | 1.0 | 643/1,182c | 1.0 | 35/84c | 1.0 | |
   5%–24% |  | 1.8 (1.5, 2.2) |  | 1.4 (1.1, 1.8) |  |  | |
   25%–49% | 1,049/1,045 | 2.1 (1.7, 2.6) | 589/835 | 2.2 (1.8, 2.8) | 66/35 | 5.5 (2.8–11) | |
   50%–74% |  | 2.9 (2.5, 3.4) | 438/665 | 2.9 (2.3, 3.8) | 34/23 | 4.8 (2.2–11) | |
   75%+ | 1,211/999 | 4.6 (3.6, 5.9) | 190/282 | 3.7 (2.7, 5.0) | 25/18 | 4.3 (1.8–10) | |
BI-RADS | 1,992/104,663b | Vacekand Geller [30] | Ziv et al. [57] | 397/1,589b | Â | Â | Â |
   Fatty | 62/7,550 | 1.0 (Ref) | 0.3 (0.2, 0.4) | 20/134 | 1.0 |  |  |
   Scattered density | 950/52,379 | 2.2 (1.6, 3.0) | 1.0 (Ref) | 216/957 | 1.6 (0.9, 2.8) |  |  |
   Heterogeneous density | 783/36,564 | 3.0 (2.2, 4.1) | 1.3 (1.1, 1.5) | 117/407 | 2.3 (1.3, 4.3) |  |  |
   Extremely dense | 197/8,170 | 4.0 (2.8, 5.7) | 20.1 (1.6, 2.8) | 44/91 | 4.5 (1.9, 10.6) |  |  |