Table 1 Clinical and reproductive characteristics among breast cancer cases and controls
Study characteristics | Case N = 419 | Control N = 286 |
|---|---|---|
Demographics | ||
 Age (years)a | 48.0 (42.0, 58.0) | 47.0 (40.0, 58.0) |
Clinical characteristics | ||
 BMI category | ||
  Underweight (< 18.5) | 21 (5.0%) | 8 (2.8%) |
  Normal weight (18.5 - < 25) | 172 (41.1%) | 106 (37.1%) |
  Overweight (25 - < 30) | 136 (32.5%) | 94 (32.9%) |
  Obese (30+) | 90 (21.5%) | 78 (27.3%) |
 BMI quartile | ||
  ≤ 22.5 | 117 (27.9%) | 60 (21.0%) |
  > 22.5 - ≤25.6 | 110 (26.3%) | 71 (24.8%) |
  > 25.6 - ≤29.8 | 99 (23.6%) | 75 (26.2%) |
  > 29.8 | 93 (22.2%) | 80 (28.0%) |
 Height, cm a | 160.0 (156.0, 164.1) | 159.7 (155.0, 163.5) |
 Weight, kg a | 64.9 (55.3, 75.8) | 66.0 (58.0, 78.0) |
 High blood pressure at enrollment | 134 (32.0%) | 95 (33.2%) |
 Systolic BP a | 126.0 (114.3, 142.3) | 128.5 (115.3, 144.0) |
 Diastolic BP a | 80.0 (70.7, 88.7) | 77.0 (70.0, 87.7) |
 Prior diabetes diagnosis | ||
  Yes | 6 (1.4) | 43 (15.0) |
  No | 411 (98.1) | 190 (66.4) |
  Missing | 2 (0.5) | 53 (18.5) |
 Prior hypertension diagnosis | 82 (19.6%) | 134 (46.9%) |
Reproductive history | ||
 Age at menarche a | 15.0 (14.0, 16.0) | 15.0 (14.0, 17.0) |
 Ever pregnant | 399 (95.2%) | 269 (94.1%) |
 Number of pregnancies a,b | 5.0 (3.0, 6.0) | 4.0 (3.0, 6.0) |
 Number of births a,b | 4.0 (3.0, 5.0) | 4.0 (2.0, 5.0) |
 Menopausal status | ||
  Pre- or peri-menopause | 207 (49.4%) | 133 (46.5%) |
  Post-menopause | 212 (50.6%) | 153 (53.5%) |
 Ever used HRT | ||
  Yes | 3 (0.7) | 41 (14.3) |
  No | 416 (99.3) | 189 (66.1) |
  Missing | 0 (0.0) | 56 (19.6) |
Cancer type | (n = 169) | n/ac |
 Luminal A | 46 (27.2%) |  |
 Luminal B | 34 (20.1%) |  |
 Triple negative | 52 (30.8%) |  |
 HER2 | 37 (21.9%) |  |
Grade | Â | n/ac |
 1 | 6 (1.4%) |  |
 2 | 132 (31.5%) |  |
 3 | 84 (20.1%) |  |
 Unknown/Missing | 197 (47.0%) |  |
Prior Mammography Screenings | 78 (18.6%) | n/ad |
Any Family History of Cancer | 21 (5.0%) | n/ad |