Table 4.
Adjusted Odds for TNBC Compared to Luminal A Tumors for Subgroups of Parity and Breastfeeding
| Luminal A n = 571 | TNBC n = 159 | ||
|---|---|---|---|
|
| |||
| No. (%) | No. (%) | OR (95% CI) | |
|
| |||
| Multivariate Modela | |||
| Breastfeeding | |||
| Never | 134 (26.1) | 23 (15.3) | 1.00 |
| Up to 12 mos | 188 (36.6) | 52 (34.7) | 1.40 (0.81–2.43) |
| >12 mos | 191 (37.2) | 75 (50.0) | 1.91 (1.09–3.36) |
| Parity | |||
| 1 to 2 children | 176 (30.8) | 39 (24.5) | 1.00 |
| ≥ 3 children | 337 (59.0) | 111 (69.8) | 1.41 (0.91–2.20) |
| Parityb stratified by Breastfeeding | |||
| Among never breastfed | |||
| 1 to 2 children | 65 (48.5) | 10 (43.5) | 1.00 |
| ≥ 3 children | 69 (51.5) | 13 (56.5) | 1.47 (0.57–3.78) |
| Per birth (excludes nulliparous) | 1.27 (0.95–1.70) | ||
| Among breastfed ≤ 12 mo | |||
| 1 to 2 children | 80 (42.6) | 20 (38.5) | 1.00 |
| ≥ 3 children | 108 (57.5) | 32 (31.5) | 1.29 (0.67–2.48) |
| Per birth (excludes nulliparous) | 1.08 (0.89–1.31) | ||
| Among breastfed > 12 mo | |||
| 1 to 2 children | 31 (16.2) | 9 (12.0) | 1.00 |
| ≥ 3 children | 160 (83.8) | 66 (88.0) | 1.54 (0.68–3.47) |
| Per birth (excludes nulliparous) | 0.95 (0.83–1.08) | ||
| Breastfeedingb stratified by parity | |||
| Among 1–2 children | |||
| Never | 65 (36.9) | 10 (25.6) | 1.00 |
| Up to 12 | 80 (45.5) | 20 (51.3) | 1.46 (0.63–3.41) |
| > 12 | 31 (17.6) | 9 (23.1) | 1.66 (0.60–4.64) |
| Per 6 mo | 1.04 (0.89–1.20) | ||
| Among 3+ children | |||
| Never | 69 (20.5) | 13 (11.7) | 1.00 |
| Up to 12 | 108 (32.1) | 32 (28.8) | 1.39 (0.67–2.87) |
| > 12 | 160 (47.5) | 66 (59.5) | 2.00 (1.00–4.03) |
| Per 6 mo | 1.04 (1.00–1.08) | ||
Abbreviations: CI, confidence interval; HER2, human epidermal growth factor receptor 2; OR, odds ratio; TNBC, triple negative breast cancer.
a
Breastfeeding and parity included in a single model, adjusted for age at diagnosis (continuous) and country (U.S. vs. Mexico).
b
Adjusted for age at diagnosis (continuous) and country (U.S. vs. Mexico).