Table 3.
Association of breastfeeding with breast cancer recurrence and death*
| Recurrence† | No. events‡ | HR | (95% CI) |
|---|---|---|---|
| Breastfeeding | |||
| Never | 190 | Ref. | |
| Ever | 193 | 0.70 | (0.53 to 0.93) |
| Lifetime breastfeeding | |||
| Never | 192 | Ref. | |
| <6 m | 77 | 0.81 | (0.58 to 1.14) |
| ≥6 mo | 116 | 0.63 | (0.46 to 0.87) |
| P trend | .01 | ||
| Breast cancer mortality† | |||
| Breastfeeding | |||
| Never | 144 | Ref. | |
| Ever | 146 | 0.72 | (0.53 to 0.98) |
| Lifetime breastfeeding | |||
| Never | 144 | Ref. | |
| <6 mo | 62 | 0.90 | (0.61 to 1.32) |
| ≥6 mo | 84 | 0.61 | (0.43 to 0.88) |
| P trend | .01 | ||
* n = 27 women had missing data on parity, surgery, chemotherapy, and/or radiotherapy and were thus excluded from all models. CI = confidence interval; HR = hazard ratio.
† Adjusted for age at diagnosis, race/ethnicity, stage, chemotherapy, radiotherapy, hormonal therapy, surgery type, PAM50 subtype, and parity.
‡ Not population based given case-cohort study design.