From: Body fatness and breast cancer risk in women of African ancestry
 | Pre-menopausal | Post-menopausal | ||||
---|---|---|---|---|---|---|
Cases | Controls | p value | Cases | Controls | p value | |
 | (n = 469) | (n = 482) |  | (n = 509) | (n = 476) |  |
n (%) | n (%) | Â | n (%) | n (%) | Â | |
Age (yrs) | Â | Â | Â | Â | Â | Â |
  Mean ± SD | 43.93 ± 6.8 | 42.65 ± 7.1 | 0.005 | 59.68 ± 6.7 | 57.70 ± 6.1 | <0.0001 |
Education | Â | Â | Â | Â | Â | Â |
  <High school | 57 (12.2) | 67 (13.9) | 0.07 | 90 (17.7) | 57 (12) | 0.003 |
  High school graduate | 133 (28.4) | 112 (23.2) |  | 165 (32.4) | 130 (27.3) |  |
  Some college | 136 (29) | 120 (24.9) |  | 122 (24) | 159 (33.4) |  |
  College graduate | 91 (19.4) | 121 (25.1) |  | 81 (15.9) | 74 (15.6) |  |
  Post-graduate degree | 52 (11.1) | 62 (12.9) |  | 51 (10) | 56 (11.8) |  |
Marital Status | Â | Â | Â | Â | Â | Â |
  Married | 184 (39.2) | 176 (36.5) | 0.05 | 158 (31.1) | 155 (32.7) | 0.19 |
  Living as married | 8 (1.7) | 9 (1.9) |  | 6 (1.2) | 11 (2.3) |  |
  Widowed | 10 (2.1) | 14 (2.9) |  | 88 (17.3) | 57 (12) |  |
  Separated | 35 (7.5) | 22 (4.6) |  | 38 (7.5) | 38 (8) |  |
  Divorced | 71 (15.1) | 55 (11.4) |  | 102 (20.1) | 93 (19.6) |  |
  Single | 161 (34.3) | 206 (42.7) |  | 116 (22.8) | 120 (25.3) |  |
Country of origin | Â | Â | Â | Â | Â | Â |
  United States | 297 (63.3) | 378 (78.4) | <0.0001 | 404 (79.4) | 391 (82.1) | 0.54 |
  Caribbean | 131 (27.9) | 75 (15.6) |  | 74 (14.5) | 61 (12.8) |  |
  Other | 41 (8.7) | 29 (6) |  | 31 (6.1) | 24 (5) |  |
Ethnicity | Â | Â | Â | Â | Â | Â |
  Hispanic | 29 (6.2) | 14 (2.9) | 0.02 | 16 (3.1) | 12 (2.5) | 0.56 |
  Non-Hispanic | 440 (93.8) | 468 (97.1) |  | 493 (96.9) | 464 (97.5) |  |
Age at menarche (yrs) | Â | Â | Â | Â | Â | Â |
  <12 | 139 (29.6) | 144 (29.9) | 0.52 | 152 (29.9) | 121 (25.5) | 0.23 |
  12-13 | 220 (46.9) | 211 (43.8) |  | 221 (43.4) | 229 (48.2) |  |
  >13 | 110 (23.5) | 127 (26.4) |  | 136 (26.7) | 125 (26.3) |  |
Age at menopause (yrs) | Â | Â | Â | Â | Â | Â |
  ≤45 |  |  |  | 70 (14.1) | 78 (16.5) | <0.001 |
  46-49 |  |  |  | 64 (12.9) | 107 (22.7) |  |
  50-54 |  |  |  | 311 (62.5) | 242 (51.3) |  |
  ≥55 |  |  |  | 53 (10.6) | 45 (9.5) |  |
Parity (livebirths) | Â | Â | Â | Â | Â | Â |
  0 | 87 (18.6) | 82 (17) | 0.17 | 67 (13.2) | 75 (15.8) | 0.17 |
  1-2 | 257 (54.8) | 241 (50) |  | 242 (47.5) | 235 (49.4) |  |
  3-4 | 104 (22.2) | 127 (26.4) |  | 137 (26.9) | 126 (26.5) |  |
  ≥5 | 21 (4.5) | 32 (6.6) |  | 63 (12.4) | 40 (8.4) |  |
Age at first birth (yrs) | Â | Â | Â | Â | Â | Â |
  Nulliparous | 87 (18.6) | 82 (17) | 0.32 | 67 (13.2) | 75 (15.8) | 0.41 |
  ≤19 | 127 (27.1) | 148 (30.7) |  | 190 (37.3) | 168 (35.4) |  |
  20-24 | 108 (23.1) | 117 (24.3) |  | 131 (25.7) | 120 (25.3) |  |
  25-30 | 89 (19) | 70 (14.5) |  | 82 (16.1) | 64 (13.5) |  |
  ≥31 | 57 (12.2) | 65 (13.5) |  | 39 (7.7) | 47 (9.9) |  |
Breastfeeding | Â | Â | Â | Â | Â | Â |
  Nulliparous | 87 (18.6) | 82 (17) | 0.32 | 67 (13.2) | 75 (15.8) | 0.34 |
  Never (among parous) | 158 (33.7) | 185 (38.4) |  | 267 (52.5) | 230 (48.3) |  |
  Ever | 224 (47.8) | 215 (44.6) |  | 175 (34.4) | 171 (35.9) |  |
Family history | Â | Â | Â | Â | Â | Â |
  No | 370 (78.9) | 416 (86.3) | 0.003 | 365 (71.7) | 389 (81.7) | <0.001 |
  Yes | 99 (21.1) | 66 (13.7) |  | 144 (28.3) | 87 (18.3) |  |
History of benign breast disease | Â | Â | Â | Â | Â | Â |
  Never | 333 (71.3) | 393 (81.7) | <0.001 | 330 (64.8) | 345 (72.5) | 0.01 |
  Ever | 134 (28.7) | 88 (18.3) |  | 179 (35.2) | 131 (27.5) |  |
HRT use | Â | Â | Â | Â | Â | Â |
  Never | 449 (96.2) | 467 (96.9) | 0.53 | 375 (74.4) | 378 (79.8) | 0.05 |
  Ever | 18 (3.9) | 15 (3.1) |  | 129 (25.6) | 96 (20.3) |  |
Oral contraceptive use | Â | Â | Â | Â | Â | Â |
  Never | 175 (37.3) | 189 (39.2) | 0.55 | 212 (41.7) | 220 (46.4) | 0.14 |
  Ever | 294 (62.7) | 293 (60.8) |  | 296 (58.3) | 254 (53.6) |  |
Smoking status | Â | Â | Â | Â | Â | Â |
  Never smoker | 297 (71.4) | 287 (60.7) | <0.001 | 219 (53.4) | 226 (52.3) | 0.13 |
  Former smoker | 62 (14.9) | 76 (16.1) |  | 127 (31) | 117 (27.1) |  |
  Current smoker | 57 (13.7) | 110 (23.3) |  | 64 (15.6) | 89 (20.6) |  |