Table 1 Baseline characteristics and in-utero exposures by case status (N = 3431)
From: Perinatal and postnatal exposures and risk of young-onset breast cancer
Characteristics mean ± SD | Controls (n = 1672) | Cases (n = 1759) |
Age at the time of case’s diagnosis | 46.3 ± 6.0 | 45.0 ± 3.9 |
Body mass index | 23.8 ± 4.4 | 23.8 ± 4.2 |
Characteristics, n (%) | n (%) | n (%) |
Age at the time of case’s diagnosis | ||
< 40 | 272 (16.3) | 211 (12.0) |
40–44 | 406 (24.3) | 491 (27.9) |
≥ 45 | 994 (59.5) | 1057 (60.1) |
Race | ||
Non-Hispanic white | 1489 (89.1) | 1520 (86.4) |
Non-Hispanic black | 73 (4.4) | 107 (6.1) |
Hispanic | 66 (3.9) | 79 (4.5) |
Other | 43 (2.6) | 53 (3.0) |
Education | ||
High school or less | 206 (12.3) | 214 (12.2) |
Some college but no degree | 273 (16.3) | 263 (15.0) |
Associate or technical degree | 260 (15.6) | 249 (14.1) |
Bachelor degree | 530 (31.7) | 589 (33.5) |
Master or doctoral degree | 403 (24.1) | 444 (25.2) |
BMI | ||
< 24.9 | 1216 (72.9) | 1257 (71.7) |
25–29.9 | 306 (18.4) | 362 (20.7) |
≥ 30 | 146 (8.8) | 134 (7.6) |
Birth order | ||
First (oldest) | 956 (57.2) | 829 (47.1) |
Second | 580 (34.7) | 871 (49.5) |
Third or younger | 136 (8.1) | 59 (3.4) |
Mother’s smoking history while pregnant with participant | ||
No | 1117 (69.5) | 1024 (69.2) |
Yes | 491 (30.5) | 455 (30.8) |
Mother’s gestational diabetes | ||
No | 1561 (99.1) | 1428 (99.2) |
Yes | 14 (0.9) | 11 (0.8) |
Mother’s preeclampsia/ eclampsia or toxemia | ||
No | 1507 (98.2) | 1359 (97.7) |
Yes | 27 (1.8) | 32 (2.3) |
Mother’s any hypertensive disorder | ||
No | 1506 (96.2) | 1368 (95.7) |
Yes | 60 (3.8) | 62 (4.3) |
Mother’s pregnancy-induced hypertension | ||
No | 1445 (97.0) | 1282 (96.7) |
Yes | 44 (3.0) | 44 (3.3) |
Was this participant breastfed? | ||
No | 948 (59.6) | 948 (64.3) |
Yes | 642 (40.4) | 527 (35.7) |
Participant’s soy formula feeding history | ||
No | 1415 (95.8) | 1221 (95.5) |
Yes | 62 (4.2) | 58 (4.5) |
Participant’s in-utero DES exposure | ||
No | 1432 (96.8) | 1252 (97.1) |
Yes | 48 (3.2) | 38 (2.9) |
Low birth weight | ||
Birth weight > 5.5 pounds | 1475 (93.3) | 1368 (91.6) |
Birth weight ≤ 5.5 pounds | 106 (6.7) | 125 (8.4) |
High birth weight | ||
Birth weight < 8.8 pounds | 1257 (92.7) | 1114 (90.6) |
Birth weight ≥ 8.8 pounds | 99 (7.3) | 115 (9.4) |
Short gestational length at birth | ||
Born ≥ 38 weeks | 988 (88.5) | 769 (84.8) |
Born < 38 weeks | 128 (11.5) | 138 (15.2) |