Table 1.
Associations between reproductive factors and breast cancer prognosis
| Variables | Overall survival | Progression‐free survival | ||||
|---|---|---|---|---|---|---|
| Fatality (%) | HR (95% CI)a | HR (95% CI)b | Progression (%) | HR (95% CI)a | HR (95% CI)b | |
| Age at first birth (y) | ||||||
| <23 | 63 (9.7) | 1.46 (1.08, 1.97) | 1.29 (0.93, 1.80) | 102 (16.1) | 1.17 (0.93, 1.47) | 1.11 (0.87, 1.43) |
| 23~30 | 134 (7.2) | 1.00 (reference) | 1.00 (reference) | 270 (14.8) | 1.00 (reference) | 1.00 (reference) |
| >30 | 20 (8.3) | 1.28 (0.80, 2.05) | 1.44 (0.87, 2.38) | 37 (15.2) | 1.15 (0.81, 1.62) | 1.20 (0.82, 1.75) |
| Intervals between first birth and diagnosis (y) | ||||||
| <10 | 22 (6.9) | 1.36 (0.76, 2.46) | 1.63 (0.87, 3.05) | 58 (18.4) | 1.43 (0.98, 2.07) | 1.49 (1.00, 2.22) |
| 10~19 | 46 (5.6) | 1.00 (reference) | 1.00 (reference) | 108 (13.4) | 1.00 (reference) | 1.00 (reference) |
| ≥20 | 149 (9.2) | 1.71 (1.14, 2.55) | 1.50 (0.94, 2.41) | 242 (15.4) | 1.22 (0.92, 1.60) | 1.25 (0.90, 1.74) |
| Intervals between last birth and diagnosis (y) | ||||||
| <10 | 34 (6.7) | 1.36 (0.78, 2.37) | 1.24 (0.69, 2.24) | 88 (17.5) | 1.40 (0.99, 2.00) | 1.27 (0.87, 1.85) |
| 10~19 | 34 (5.4) | 1.00 (reference) | 1.00 (reference) | 80 (13.0) | 1.00 (reference) | 1.00 (reference) |
| ≥20 | 127 (9.2) | 1.84 (1.19, 2.84 ) | 1.60 (0.95, 2.68) | 204 (15.2) | 1.25 (0.93, 1.68) | 1.26 (0.88, 1.80) |
| Intervals between first and second birth (y) | ||||||
| ≤5 | 121 (10.2) | 1.00 (reference) | 1.00 (reference) | 204 (17.6) | 1.00 (reference) | 1.00 (reference) |
| >5 | 18 ( 6.3) | 0.60 (0.36, 1.00) | 0.71 (0.41, 1.22) | 36 (12.6) | 0.69 (0.48, 1.00) | 0.64 (0.42, 0.97) |
| Parity | ||||||
| 0 | 16 (9.1) | 1.20 (0.72, 2.03) | 1.01 (0.54, 1.88) | 25 (14.6) | 0.93 (0.61, 1.40) | 0.94 (0.60, 1.47) |
| 1~2 | 162 (7.3) | 1.00 (reference) | 1.00 (reference) | 309 (14.2) | 1.00 (reference) | 1.00 (reference) |
| ≥3 | 58 (9.9) | 1.38 (1.01, 1.88) | 0.96 (0.68, 1.36) | 108 (19.0) | 1.42 (1.13, 1.78) | 1.07 (0.83, 1.40) |
| Abortion | ||||||
| Never | 102 (8.0) | 1.00 (reference) | 1.00 (reference) | 192 (15.5) | 1.00 (reference) | 1.00 (reference) |
| Ever | 125 (8.0) | 0.90 (0.69, 1.17) | 0.98 (0.74, 1.31) | 228 (14.9) | 0.91 (0.75, 1.11) | 0.92 (0.75, 1.13) |
| No. of abortions | ||||||
| 0 | 102 (8.0) | 1.00 (reference) | 1.00 (reference) | 192 (15.5) | 1.00 (reference) | 1.00 (reference) |
| 1 | 64 (8.2) | 0.92 (0.67, 1.26) | 1.02 (0.73, 1.43) | 109 (14.3) | 0.86 (0.68, 1.10) | 0.90 (0.70, 1.15) |
| ≥2 | 61 (7.8) | 0.89 (0.65, 1.22) | 0.95 (0.67, 1.34) | 119 (15.4) | 0.96 (0.76, 1.21) | 0.95 (0.74, 1.22) |
Abbreviations: ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; HR, hazard ratio.
Bold character indicates statistically significant result.
a
Adjusted for age at diagnosis.
b
Adjusted for age at diagnosis, education, menopausal status, clinical stage, ER status, HER2 status.