Table 1.
Baseline Characteristics of Participants in the WHI CEE-alone Trial by Breast Tenderness Status at Year 1*
| Characteristic | No tenderness at year 1 (N=6218) | Tenderness at year 1 (N=1793) | P† |
|---|---|---|---|
| Age at screening, mean (SD), y | 63.9 (7.2) | 64.6(7.2) | <0.001 |
| Treatment assignment, No. (%) | <0.001 | ||
| CEE Placebo | 3463 (55.7) | 575 (32.1) | |
| CEE Active | 2755 (44.3) | 1218 (67.9) | |
| Ethnicity, No (%) | 0.06 | ||
| White | 4926 (79.2) | 1382 (77.1) | |
| Black | 794 (12.8) | 260 (14.5) | |
| Hispanic | 280 (4.5) | 88 (4.9) | |
| American Indian | 39 (0.6) | 10 (0.6) | |
| Asian/Pacific Islander | 97 (1.6) | 24 (1.3) | |
| Unknown | 82 (1.3) | 29 (1.6) | |
| Daily alcohol intake, No. (%) | 0.66 | ||
| Non drinker | 3086 (49.9) | 913 (51.1) | |
| ≤ 1 drink | 2509 (40.5) | 716 (40.1) | |
| > 1 drink | 595 (9.6) | 158 (8.8) | |
| Smoking status, No. (%) | 0.27 | ||
| Never | 3165 (51.4) | 919 (51.6) | |
| Past | 2369 (38.5) | 710 (39.9) | |
| Current | 623 (10.1) | 151 (8.5) | |
| Regular cups of coffee/day, No. (%) | 0.41 | ||
| None | 2280 (37.0) | 650 (36.5) | |
| 1 | 917 (14.9) | 266 (14.9) | |
| 2 | 1253 (20.3) | 393 (22.1) | |
| ≥ 3 | 1712 (27.8) | 472 (26.5) | |
| BMI (kg/m2), No. (%) | 0.03 | ||
| < 25 | 1399 (22.6) | 359 (20.2) | |
| 25–<30 | 2168 (35.0) | 626 (35.1) | |
| 30–<35 | 1482 (23.9) | 467 (26.2) | |
| 35–<40 | 745 (12.0) | 227 (12.7) | |
| ≥40 | 396 (6.4) | 102 (5.7) | |
| Quartiles of physical activity, MET h/wk, No. (%) | 0.07 | ||
| < 1.5 | 1458 (25.7) | 447 (27.2) | |
| 1.5 to 6.5 | 1517 (26.7) | 446 (27.1) | |
| 6.5 to 15.75 | 1390 (24.5) | 417 (25.4) | |
| ≥ 15.75 | 1311 (23.1) | 333 (20.3) | |
| Parity, No. (%) | 0.56 | ||
| Never pregnant/Never had term pregnancy | 567 (9.2) | 154 (8.6) | |
| 1 | 482 (7.8) | 129 (7.2) | |
| 2 | 1248 (20.2) | 377 (21.1) | |
| ≥3 | 3883 (62.8) | 1126 (63.0) | |
| Age at first birth, No, (%) | 0.90 | ||
| Never pregnant/never had term pregnancy | 567 (10.1) | 154 (9.7) | |
| < 20 years | 1327 (23.5) | 365 (23.1) | |
| 20 – 29 years | 3453 (61.2) | 984 (62.2) | |
| ≥ 30 years | 291 (5.2) | 80 (5.1) | |
| Age at menarche, No. (%) | 0.04 | ||
| <12 years | 1455 (23.5) | 387 (21.6) | |
| 12–13 years | 3281 (53.0) | 1012 (56.6) | |
| ≥14 years | 1458 (23.5) | 389 (21.8) | |
| Years since menopause, No. (%) | 0.01 | ||
| <5 | 354 (6.7) | 89 (5.8) | |
| 5–10 | 585 (11.1) | 122 (7.9) | |
| 11–14 | 847 (16.1) | 232 (15.0) | |
| ≥15 | 3474 (66.0) | 1101 (71.3) | |
| Prior benign breast disease, No. (%) | <0.001 | ||
| Never | 4589 (81.8) | 1263 (77.9) | |
| 1 biopsy | 755 (13.5) | 255 (15.7) | |
| 2+ biopsies | 264 (4.7) | 103 (6.4) | |
| Family history of female relative w/breast cancer, No. (%) | 980 (16.7) | 324 (19.3) | 0.01 |
| Bilateral oophorectomy, No. (%) | 2374 (41.1) | 701 (41.8) | 0.69 |
| Age when both ovaries removed, No. | 0.17 | ||
| < 40 years | 598(25.4) | 200 (28.8) | |
| 40–49 years | 1161 (49.4) | 323 (46.5) | |
| 50–54 years | 355 (15.1) | 95 (13.7) | |
| ≥ 55 years | 237 (10.1) | 76 (11.0) | |
| Age at hysterectomy, No. (%) | 0.14 | ||
| < 40 years | 2340 (37.9) | 694 (38.9) | |
| 40–49 years | 2691 (43.6) | 775 (43.4) | |
| 50–54 years | 648 (10.5) | 182 (10.2) | |
| ≥ 55 years | 500 (8.1) | 135 (7.6) | |
| Duration of breastfeeding, No. (%) | 0.52 | ||
| Never | 2893 (47.3) | 797 (45.3) | |
| ≤ 1 year | 2375 (38.8) | 703 (39.9) | |
| > 1 year | 850 (13.9) | 260 (14.8) | |
| Quartiles of 5-year Gail model risk scores, | 0.29 | ||
| No. (%) | |||
| < 1.1 | 1583 (25.5) | 442 (24.7) | |
| 1.1 to < 1.44 | 1574 (25.3) | 418 (23.3) | |
| 1.44 to < 1.91 | 1547 (24.9) | 453 (25.3) | |
| ≥ 1.91 | 1514 (24.3) | 480 (26.8) | |
| Pre-trial use of estrogen therapy, No. (%) | 0.01 | ||
| Never used | 3310 (53.2) | 951 (53.1) | |
| Past user | 2097 (33.7) | 657 (36.7) | |
| Current user | 810 (13.0) | 184 (10.3) | |
| Pre-trial use of estrogen + progesterone* therapy, No. (%) | 0.72 | ||
| Never used | 5944 (95.6) | 1715 (95.6) | |
| Past user | 243 (3.9) | 68 (3.8) | |
| Current user | 31 (0.5) | 10 (0.6) |
*
Of the 10739 WHI CEE-alone trial participants, information regarding baseline and year 1 breast tenderness was available for 9620 participants. Thus, this table excludes participants for whom information regarding breast tenderness was missing from the baseline visit (n=86), the year 1 visit (n=1014), and both (n=19).
†
Compares baseline characteristics of participants without vs with new-onset breast tenderness after adjustment for age and treatment assignment. Tests of association for age and treatment assignment are unadjusted.
*
Self-reported at screening interview