Table 5.
Hazard ratios (HR) and 95% confidence intervals (CI) for breast cancer-specific mortality according to body mass index, strati-fied by AJCC stage at diagnosis
| N | Breast cancer-specific mortalitya |
|||
|---|---|---|---|---|
| HR | 95% CI | p value for trend | ||
| Stage I (N = 2414) | ||||
| Body mass index (kg/m2) | ||||
| < 18.5 | 39 | 2.33 | 0.54–10.08 | |
| 18.5–24.9 | 788 | 1 (ref) | ||
| 25–29.9 | 739 | 1.47 | 0.67–3.20 | |
| 30–34.9 | 475 | 1.06 | 0.45–2.52 | |
| ≥ 35 | 373 | 4.74 | 1.78–12.59 | |
| Per 5 kg/m2 Δ | 1.38 (1.22–1.55) | 0.004 | ||
| Stage II (N = 2060) | ||||
| Body mass index (kg/m2) | ||||
| < 18.5 | 27 | Not estimable | 0.51 | |
| 18.5–24.9 | 594 | 1 (ref) | ||
| 25–29.9 | 584 | 0.88 | 0.53–1.47 | |
| 30–34.9 | 448 | 0.80 | 0.47–1.35 | |
| ≥ 35 | 407 | 0.87 | 0.48–1.58 | |
| Stage III (N = 815) | ||||
| Body mass index (kg/m2) | ||||
| < 18.5 | 10 | 0.32 | 0.06–1.84 | 0.20 |
| 18.5–24.9 | 216 | 1 (ref) | ||
| 25–29.9 | 231 | 0.74 | 0.47–1.17 | |
| 30–34.9 | 183 | 0.97 | 0.62–1.54 | |
| ≥35 | 175 | 0.69 | 0.41–1.17 | |
p value for interaction term (stage*BMI) = 0.04
a
All models adjusted for age, insurance type, poverty in census tract of residence, education levels in census tract of residence, urbanicity of residence area, tumor grade, hormone receptor status, and comor-bidity level. Survey sampling was stratified by tumor registry and by race/ethnicity