Table 1 Selected characteristics of the women in the study
From: A prospective case–cohort analysis of plasma metabolites and breast cancer risk
Characteristic | Breast cancer cases N = 1687 | Subcohort N = 1983 |
|---|---|---|
N (%) | N (%) | |
Age (year) | ||
< 40 | 148 (8.8) | 496 (25.0) |
40–49 | 498 (29.5) | 527 (26.6) |
50–59 | 716 (42.4) | 693 (34.9) |
≥ 60 | 327 (19.4) | 267 (13.5) |
Race | ||
White | 1466 (86.8) | 1653 (83.4) |
Black | 62 (3.7) | 85 (4.3) |
Hispanic | 101 (6.0) | 150 (7.6) |
Other/Missing | 60 (3.6) | 95 (4.8) |
Education | ||
High school or less | 229 (13.6) | 177 (8.9) |
Some college/2-year degree | 522 (30.9) | 589 (29.7) |
College graduate | 461 (27.3) | 631 (31.8) |
Graduate degree | 395 (23.4) | 511 (25.8) |
Missing/Unclear | 82 (4.9) | 75 (3.8) |
Family history of breast cancer | ||
No | 1099 (65.1) | 1466 (73.9) |
Yes | 322 (19.1) | 221 (11.1) |
Missing | 268 (15.9) | 296 (14.9) |
BMI category (kg/m2) | ||
< 18.5 | 9 (0.5) | 26 (1.3) |
18.5–22.4 | 296 (17.5) | 419 (21.1) |
22.5–24.9 | 297 (17.6) | 415 (20.9) |
25.0–29.9 | 529 (31.3) | 512 (25.8) |
≥ 30 | 542 (32.1) | 593 (29.9) |
Missing | 16 (0.9) | 18 (0.9) |
Smoking status | ||
Never smoker | 1085 (64.2) | 1335 (67.3) |
Current smoker | 83 (4.9) | 102 (5.1) |
Former smoker | 507 (30.0) | 542 (27.3) |
Missing | 14 (0.8) | 4 (0.2) |
Time since last meal (h) | 1.99 | 2.01 |
Time from blood draw to processing (h) | 14.53 | 14.78 |
Age at menarche (year) | ||
≤ 11 | 389 (23.0) | 423 (21.3) |
12 | 461 (27.3) | 545 (27.5) |
13 | 476 (28.2) | 578 (29.1) |
≥ 14 | 328 (19.4) | 402 (20.3) |
Missing | 35 (2.1) | 35 (1.8) |
Age at first birth and parity | ||
Nulliparous | 308 (18.2) | 437 (22.0) |
Age < 25, 1–2 births | 293 (17.3) | 310 (15.6) |
Age < 25, 3+ births | 176 (10.4) | 204 (10.3) |
Age 25+ , 1–2 births | 576 (34.1) | 633 (31.9) |
Age 25+ , 3+ births | 138 (8.2) | 165 (8.3) |
Unknown | 198 (11.7) | 234 (11.8) |
Age at menopause [mean, yr(SD)] | 48.3 (6.5) | 47.3 {6.9) |
Menopausal status | ||
Premenopausal | 731 (43.3) | 1038 (52.3) |
Postmenopausal | 874 (51.7) | 842 (42.5) |
Unknown/Incomplete | 84 (5.0) | 103 (5.2) |
Oral contraceptive use | ||
Never | 182 (10.8) | 206 (10.4) |
Current | 142 (8.4) | 198 (10.0) |
Former | 1327 (78.6) | 1542 (77.8) |
Missing | 38 (2.2) | 37 (1.9) |
Postmenopausal hormone use | ||
Never | 1177 (69.7) | 1486 (74.9) |
Current | 165 (9.8) | 159 (8.0) |
Former | 230 (13.6) | 241 (12.2) |
Missing | 117 (6.9) | 97 (4.9) |
Estrogen receptor status | ||
ER+ | 1410 (83.5) | 14 (0.7) |
ER− | 252 (14.9) | 0 (0) |
Missing | 27 (1.6) | 0 (0) |
Breast cancer stage | ||
Localized | 1154 (68.3) | 11 (0.6) |
Regional | 486 (28.8) | 3 (0.2) |
Distant | 49 (2.9) | 0 (0) |
Unknown | 0 (0) | 0 (0) |