Table 1 Association between standardized percent mammographic breast density change and breast cancer risk factors by case–control status
Characteristic | Cases (n = 261) | Controls (n = 249) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
% | Baseline MBD Mean (Range) | Stable/any increase (n = 65, 24.9%) N (%) | Minimal decrease (n = 151, 57.9%) N (%) | Decrease (n = 45, 17.2%) N (%) | p-value* | % | Baseline MBD Mean (Range) | Stable/any increase (n = 65, 26.1%) N (%) | Minimal decrease (n = 132, 53.0%) N (%) | Decrease (n = 52, 20.9%) N (%) | p-value* | |
BBD histotype | ||||||||||||
  Normal/Non-proliferative | 57.9 | 33.6 (2.3, 83.7) | 40 (61.5) | 85 (56.3) | 26 (57.8) | 0.77 | 71.5 | 31.8 (2.4, 82.3) | 43 (66.2) | 100 (75.8) | 35 (75.8) | 0.28 |
  Proliferative diagnosis (with/out  atypia) | 42.1 | 34.7 (3.7, 81.6) | 25 (38.5) | 66 (43.7) | 19 (42.2) |  | 28.5 | 29.1 (0.2, 75.0) | 22 (33.9) | 32 (24.2) | 17 (24.2) |  |
Age at BBD (years) | ||||||||||||
   < 50 | 36.0 | 42.1 (8.3, 83.7) | 13 (20.0) | 62 (41.1) | 19 (42.2) |  < 0.0001 | 31.7 | 37.7 (3.4, 77.6) | 13 (20.0) | 53 (40.2) | 13 (40.2) | 0.0062 |
  50–59 | 34.5 | 34.1 (2.7, 79.7) | 18 (27.7) | 58 (38.4) | 14 (31.1) |  | 35.7 | 30.8 (5.2, 82.3) | 21 (32.3) | 45 (34.1) | 23 (34.1) |  |
   ≥ 60 | 29.5 | 24.2 (2.3, 62.3) | 34 (52.3) | 31 (20.5) | 12 (26.7) |  | 32.5 | 24.8 (0.2, 79.4) | 31 (47.7) | 34 (25.8) | 16 (25.8) |  |
  Median (range) |  | 54.2 (32.6, 86.6) | 61.3 (35.9, 86.6) | 52.7 (32.6, 78.6) | 51.8 (36.2, 78.5) |  |  | 55.0 (32.4, 86.2) | 59.8 (32.4, 86.2) | 52.3 (36.0, 78.7) | 55.0 (38.8, 73.6) |  |
Parity/age at first live birth (ALFB) | ||||||||||||
  Nulliparous/AFLB ≥ 30 years | 23.7 | 40.2 (2.7, 81.6) | 12 (19.1) | 38 (25.0) | 12 (25.8) | 0.54 | 22.7 | 37.9 (0.2, 82.3) | 12 (18.2) | 33 (25.2) | 11 (21.9) | 0.58 |
  Parous/AFLB < 30 years | 76.3 | 32.2 (2.3, 83.7) | 53 (80.9) | 113 (75.0) | 33 (74.2) |  | 77.3 | 29.0 (1.1, 79.4) | 53 (81.8) | 99 (74.8) | 41 (78.1) |  |
BMI at biopsy (kg/m2) | ||||||||||||
   < 25 | 35.5 | 43.5 (2.3, 83.7) | 20 (30.8) | 58 (38.4) | 14 (31.1) | 0.69 | 37.3 | 41.1 (4.9, 82.3) | 19 (29.2) | 55 (41.7) | 19 (36.5) | 0.0083 |
  25–29 | 36.6 | 30.1 (3.7, 74.4) | 28 (43.1) | 51 (33.8) | 18 (40.0) |  | 33.5 | 27.8 (0.2, 74.6) | 16 (24.6) | 46 (24.9) | 22 (42.3) |  |
   ≥ 30 | 28.0 | 27.3 (2.7, 81.6) | 17 (26.2) | 42 (27.8) | 13 (28.9) |  | 29.2 | 21.8 (1.1, 64.9) | 30 (46.2) | 31 (23.5) | 11 (21.2) |  |
Family history | ||||||||||||
  Absent | 77.9 | 34.5 (2.7, 83.7) | 47 (72.0) | 120 (79.2) | 37 (81.8) | 0.41 | 82.6 | 31.3 (0.2, 82.3) | 58 (88.6) | 107 (81.4) | 41 (78.1) | 0.31 |
  Present | 22.1 | 32.7 (2.3, 81.6) | 18 (28.0) | 31 (20.8) | 8 (18.2) |  | 17.4 | 29.4 (3.7, 79.4) | 7 (11.4) | 25 (18.6) | 11 (21.9) |  |
Menopause and MHT use | ||||||||||||
  Premenopausal | 38.5 | 41.2 (6.6, 83.7) | 14 (21.5) | 69 (45.7) | 18 (40.0) | – | 32.8 | 38.3 (3.4, 77.6) | 14 (21.5) | 53 (40.2) | 15 (28.9) | 0.16 |
  Postmenopausal MHT use | 43.8 | 29.7 (2.3, 72.5) | 38 (58.5) | 57 (37.8) | 18 (40.0) |  | 53.2 | 28.6 (1.1, 82.3) | 38 (58.5) | 64 (48.5) | 30 (57.7) |  |
  Postmenopausal No MHT | 0.8 | 15.0 (7.7, 22.2) | 0 | 1 (0.7) | 1 (2.2) |  | 4.1 | 22.1 (4.9, 37.7) | 4 (6.2) | 5 (3.8) | 1 (1.9) |  |
  Postmenopausal Unknown MHT | 16.9 | 29.9 (2.7, 79.7) | 13 (20.0) | 24 (15.9) | 8 (17.8) |  | 10.0 | 23.6 (0.2, 57.1) | 9 (13.9) | 10 (7.6) | 6 (11.5) |  |
Impression of involution | ||||||||||||
  None/mildly involuted (0–24%) | 57.5 | 35.3 (4.0, 79.7) | 22 (44.) | 87 (64.9) | 18 (47.4) | 0.016 | 47.6 | 33.3 (3.4, 77.6) | 21 (45.7) | 57 (50.0) | 20 (43.5) | 0.18 |
  Partially involuted (25–74%) | 19.9 | 36.0 (8.3, 74.4) | 9 (18.4) | 23 (17.2) | 12 (31.6) |  | 18.5 | 37.8 (8.5, 82.3) | 7 (15.2) | 17 (14.9) | 14 (30.4) |  |
  Completely involuted (≥ 75%) | 22.6 | 33.6 (2.3, 83.7) | 18 (36.7) | 24 (17.9) | 8 (21.1) |  | 34.0 | 29.5 (2.4, 69.2) | 18 (39.1) | 40 (35.1) | 12 (26.1) |  |
  No TDLU observed |  | 28.4 (2.7, 81.6) | 16 | 17 | 7 |  |  | 22.1 (0.2, 70.4) | 19 | 18 | 6 |  |
Epithelial-to-Stroma proportion | ||||||||||||
  Low | 37.1 | 36.6 (6.3, 83.7) | 22 (36.1) | 57 (39.3) | 12 (30.8) | 0.61 | 49.8 | 31.7 (0.2, 75.0) | 30 (48.4) | 68 (54.8) | 19 (54.8) | 0.16 |
  High | 62.9 | 32.4 (2.3, 81.6) | 39 (63.9) | 88 (60.7) | 27 (69.2) |  | 50.2 | 30.2 (1.1, 82.3) | 32 (51.6) | 56 (45.2) | 30 (45.2) |  |
Epithelium | ||||||||||||
  Low | 43.3 | 31.6 (2.3, 83.7) | 28 (45.9) | 63 (43.5) | 15 (38.5) | 0.76 | 51.1 | 29.1 (0.2, 70.4) | 34 (54.8) | 60 (48.4) | 26 (48.4) | 0.67 |
  High | 56.7 | 35.7 (3.7, 81.6) | 33 (54.1) | 82 (56.6) | 24 (61.5) |  | 48.9 | 32.9 (1.1, 82.3) | 28 (45.2) | 64 (51.6) | 23 (51.6) |  |
Stroma | ||||||||||||
  Low | 48.2 | 28.2 (2.3, 73.6) | 30 (49.2) | 70 (48.3) | 18 (46.2) | 0.96 | 49.8 | 26.6 (0.2, 82.3) | 37 (59.7) | 51 (41.1) | 29 (41.1) | 0.020 |
  High | 51.8 | 39.3 (5.0, 83.7) | 31 (50.8) | 75 (51.7) | 21 (53.9) |  | 50.2 | 35.3 (1.6, 77.0) | 25 (40.3) | 73 (58.9) | 20 (58.9) |  |
Adipose tissue | ||||||||||||
  Low | 55.9 | 38.9 (5.0, 83.7) | 32 (52.5) | 81 (55.9) | 24 (61.5) | 0.67 | 50.2 | 35.2 (1.1, 79.4) | 27 (43.6) | 69 (55.7) | 22 (55.7) | 0.21 |
  High | 44.1 | 27.7 (2.3, 63.2) | 29 (47.5) | 64 (44.1) | 15 (38.5) |  | 49.8 | 26.7 (0.2, 82.3) | 35 (56.5) | 55 (44.4) | 27 (44.4) |  |
Baseline MBD (%) | ||||||||||||
  Q1: ≤ 15.1 | 16.5 | – | 24 (36.9) | 17 (11.3) | 2 (4.4) |  < 0.0001 | 25.3 | – | 35 (53.9) | 27 (20.5) | 1 (1.9) |  < 0.0001 |
  Q2: 15.1 < to ≤ 28.9 | 26.8 | – | 22 (33.9) | 41 (27.2) | 7 (15.6) |  | 24.9 | – | 18 (27.7) | 34 (25.8) | 10 (19.2) |  |
  Q3: 28.9 < to ≤ 43.6 | 27.2 | – | 10 (15.4) | 47 (31.1) | 14 (31.1) |  | 24.9 | – | 7 (10.8) | 36 (27.3) | 19 (36.5) |  |
  Q4: >43.6 | 29.5 | – | 9 (13.9) | 46 (30.5) | 22 (48.9) |  | 24.9 | – | 5 (7.7) | 35 (26.5) | 22 (42.3) |  |