Table 1 Selected characteristics of the study population by menopausal status and case status (Nurses’ Health Study, 1989–2006)
From: Prolactin levels and breast cancer risk by tumor expression of prolactin-related markers
Population characteristics | Premenopausal (168 cases/765 controls) | Postmenopausal (577 cases/1689 controls) | ||
|---|---|---|---|---|
Mean (SD) | Mean (SD) | |||
Age at blood collection* | 49.5 (3.8) | 49.6 (3.5) | 62.7 (6.5) | 62.7 (6.3) |
Age at menarche | 12.3 (1.4) | 12.4 (1.3) | 12.5 (1.4) | 12.6 (1.4) |
BMI at blood collection | 24.7 (4.0) | 25.5 (4.7) | 26.0 (4.7) | 25.8 (4.5) |
Prolactin (ng/mL) | 15.1 (9.2) | 14.3 (8.8) | 12.0 (7.7) | 11.4 (7.7) |
Breastfeeding (months) | 9.1 (12.0) | 7.6 (10.9) | 7.1 (10.9) | 5.7 (9.3) |
Time from blood collection to diagnosis (years) | 6.0 (3.0) | Â | 4.7 (3.1) | Â |
| Â | N (%) | N (%) | ||
|---|---|---|---|---|
Fasting at blood collection* | 106 (63.1) | 481 (62.9) | 411 (71.2) | 1205 (71.3) |
Family history of breast cancer | 18 (10.7) | 63 (8.2) | 99 (17.2) | 224 (13.3) |
Parity | ||||
 Nulliparous | 12 (7.1) | 45 (5.9) | 37 (6.4) | 103 (6.1) |
 1 child | 12 (7.1) | 50 (6.5) | 37 (6.4) | 105 (6.2) |
 2 children | 52 (31.0) | 267 (34.9) | 143 (24.8) | 372 (22.0) |
 3 children | 57 (33.9) | 243 (31.8) | 168 (29.1) | 466 (27.6) |
 4 or more children | 35 (20.8) | 160 (20.9) | 192 (33.3) | 643 (38.1) |
History of BBD | ||||
 Biopsy-confirmed | 37 (22.0) | 124 (16.2) | 124 (21.5) | 276 (16.3) |
 Unconfirmed or confirmation unknown | 64 (38.1) | 251 (32.8) | 188 (32.6) | 485 (28.7) |
HT use at blood collection* | – | – | 344 (59.6) | 721 (42.7) |
Invasive status | ||||
 Invasive | 140 (83.3) |  | 494 (85.6) |  |
 DCIS | 28 (16.7) |  | 83 (14.4) |  |
ER status | ||||
 Negative | 30 (17.9) |  | 103 (17.9) |  |
 Positive | 137 (81.5) |  | 462 (80.1) |  |
 Unknown | 1 (0.6) |  | 12 (2.1) |  |
PR status | ||||
 Negative | 44 (26.2) |  | 148 (25.6) |  |
 Positive | 124 (73.8) |  | 422 (73.1) |  |
 Unknown | – |  | 7 (1.2) |  |
HER-2 status | ||||
 Negative | 110 (65.5) |  | 433 (75.0) |  |
 Positive | 54 (32.1) |  | 127 (22.0) |  |
 Unknown | 4 (2.4) |  | 17 (2.9) |  |
Tumor marker (score) | ||||
 PRLR nuclear | ||||
  Negative (0/1) | 134 (79.8) |  | 406 (70.4) |  |
  Positive (2/3) | 29 (17.3) |  | 139 (24.1) |  |
  Unknown | 5 (3.0) |  | 32 (5.5) |  |
 PRLR cytoplasmic | ||||
  Negative (0/1) | 128 (76.2) |  | 416 (72.1) |  |
  Positive (2/3) | 35 (20.8) |  | 129 (22.4) |  |
  Unknown | 5 (3.0) |  | 32 (5.5) |  |
 pSTAT5 nuclear | ||||
  Negative (0/1) | 117 (69.6) |  | 394 (68.3) |  |
  Positive (2/3) | 35 (20.8) |  | 125 (21.7) |  |
  Unknown | 16 (9.5) |  | 58 (10.1) |  |
 pSTAT5 cytoplasmic | ||||
  Negative (0) | 61 (36.3) |  | 213 (36.9) |  |
  Positive (1/2) | 91 (54.2) |  | 306 (53.0) |  |
  Unknown | 16 (9.5) |  | 58 (10.1) |  |
 pJAK2 | ||||
  Negative (0) | 20 (11.9) |  | 95 (16.5) |  |
  Positive (1/2) | 127 (75.6) |  | 409 (70.9) |  |
  Unknown | 21 (12.5) |  | 73 (12.7) |  |