Table 1.
Descriptive characteristics of invasive breast cancer cases and matched controls
| Cases (n = 1762) | Controls (n = 1890) | |
|---|---|---|
| Cohort, n | ||
| BGS | 230 | 230 |
| CLUE II | 87 | 87 |
| CSB | 69 | 69 |
| Guernsey | 124 | 124 |
| NHS | 93 | 93 |
| NHS II | 248 | 250 |
| NSMSC | 31 | 31 |
| NYUWHS | 493 | 496 |
| ORDET | 214 | 224 |
| Sister | 173 | 286 |
| Age at blood donation, years, n (%) | ||
| 35–40 | 472 (26.8) | 487 (25.8) |
| 41–45 | 708 (40.2) | 752 (39.8) |
| 46–50a | 582 (33.0) | 651 (34.5) |
| Race/ethnicity, n (%) | ||
| White | 1587 (90.1) | 1696 (89.7) |
| Black/African American | 76 (4.3) | 73 (3.9) |
| Other or missing | 99 (5.6) | 121 (6.4) |
| Age at diagnosis, years, n (%) | ||
| 35–45 | 287 (16.3) | |
| 46–50 | 579 (32.9) | |
| 51–55 | 436 (24.7) | |
| 56–60 | 235 (13.3) | |
| 61–65 | 141 (8.0) | |
| > 65 | 84 (4.8) | |
| Lag time between blood donation and diagnosis, years, n (%) | ||
| 0–2 | 274 (15.6) | |
| 3–5 | 420 (23.8) | |
| 6–10 | 443 (25.1) | |
| 11–15 | 286 (16.2) | |
| 16–20 | 201 (11.4) | |
| > 20 | 138 (7.8) | |
| Age at menarche, years, n (%) | ||
| < 12 | 376 (21.3) | 411 (21.7) |
| 12–13 | 976 (55.4) | 1012 (53.5) |
| ≥14 or missingb | 410 (23.3) | 467 (24.7) |
| Age at first live birth, years, n (%) | ||
| < 20 or missingb | 114 (6.5) | 143 (7.6) |
| 20–24 | 457 (25.9) | 521 (27.6) |
| 25–29c | 473 (26.8) | 511 (27.1) |
| ≥ 30 | 304 (17.3) | 307 (16.2) |
| Nulliparous | 414 (23.5) | 408 (21.5) |
| Number of benign breast biopsies, n (%) | ||
| 0 or missingb | 1339 (76.0) | 1559 (82.5) |
| ≥ 1 | 423 (24.0) | 331 (17.5) |
| 0 | 1311 (74.4) | 1415 (74.9) |
| 1d | 382 (21.7) | 412 (21.8) |
| > 1d | 69 (3.9) | 63 (3.3) |
| BMI, kg/m2, n (%) | ||
| < 25 | 1097 (59.9) | 1124 (62.6) |
| 25–29 | 420 (24.8) | 465 (24.0) |
| ≥ 30 | 234 (15.4) | 289 (13.4) |
| Missing | 11 | 12 |
| AMH cohort-specific quartiles, n(%) | ||
| Q1 | 365 (20.7) | 480 (25.4) |
| Q2 | 444 (25.1) | 468 (24.8) |
| Q3 | 453 (25.7) | 468 (24.8) |
| Q4 | 500 (28.4) | 474 (25.1) |
| Testosterone cohort-specific quartiles, n (%) | ||
| Q1 | 423 (24.0) | 511 (27.0) |
| Q2 | 414 (23.5) | 464 (24.6) |
| Q3 | 452 (25.7) | 460 (24.3) |
| Q4 | 473 (26.8) | 455 (24.1) |
| BCRAT 5-year risk score (%), n (%)e | ||
| < 0.6% | 296 (16.8) | 332 (17.6) |
| 0.6–0.99% | 679 (38.5) | 765 (40.5) |
| 1–1.66% | 525 (29.8) | 517 (27.3) |
| 1.67–1.99% | 110 (6.2) | 130 (6.9) |
| 2–2.99% | 115 (6.5) | 115 (6.1) |
| ≥ 3% | 37 (2.1) | 31 (1.6) |
| ER status, n (%) | ||
| ER-positive | 1139 (79.8) | |
| ER-negative | 289 (20.2) | |
| Unknown | 334 | |
Note: Cases and controls were matched 1:1 for all cohorts except for Sister Study which matched 1:2
aAll cases had age at blood donation ≤ 50, though for 24 sets, matched controls ages were ≤ 51.2 years at blood donation
bTo be consistent with BCRAT, which imputes missing data to the lowest risk category, we imputed missing data as follows: age at menarche: ≥ 14 for 35 cases (1.5%) and 49 controls (1.9%); age at first live birth: < 20 for 5 cases (0.2%) and 7 (0.3%) controls; number of breast biopsies: 0 for 42 cases (1.8%) and 40 controls (1.6%)
cAs done in BCRAT, nulliparous and women who were 25–29 at first birth were combined in all models
dThe number of first-degree family members with breast cancer was coded as 0, 1, or > 1 affected relatives. For cohorts that collected family history as a no/yes variable, “yes” answers were assigned to the intermediate category (1 affected relative)
eCalculated using the following variables: race, age at menarche, age at first live birth, number of breast biopsies, and number of first-degree family members with breast cancer, history of atypical hyperplasia was missing for all cohorts and set to “no.” Gail model 2 rates and parameters were used as described in [14]