Table 3. Breast cancer-specific mortality in relation to body mass index before diagnosis, by the use of HRT or by detection mode: the Swedish Breast Cancer Study 1993–2003.
| Breast cancer deaths/exposed | Breast cancer mortality ratea | HRb | 95% CI | HRc | 95% CI | |
|---|---|---|---|---|---|---|
| All women | ||||||
| BMI | ||||||
| <25 | 162/1090 | 1.8 | 1.0 | Ref. | 1.0 | Ref. |
| 25–30 | 126/873 | 1.7 | 1.0 | 0.8, 1.2 | 0.9 | 0.7, 1.2 |
| >30 | 66/322 | 2.6 | 1.4 | 1.1, 1.9 | 1.2 | 0.9, 1.6 |
| Never hormone replacement therapy | ||||||
| BMI | ||||||
| <25 | 108/628 | 2.1 | 1.0 | Ref. | 1.0 | Ref. |
| 25–30 | 99/645 | 1.9 | 0.9 | 0.7, 1.2 | 0.8 | 0.6, 1.1 |
| >30 | 45/243 | 2.3 | 1.1 | 0.8, 1.6 | 0.9 | 0.6, 1.3 |
| Ever oestrogen–progestin therapy | ||||||
| BMI | ||||||
| <25 | 36/329 | 1.2 | 1.0 | Ref. | 1.0 | Ref. |
| 25–30 | 10/130 | 0.9 | 0.8 | 0.4, 1.6 | 1.0 | 0.5, 2.1 |
| >30 | 13/40 | 4.3 | 3.7 | 1.9, 7.2 | 2.3 | 1.1, 5.2 |
| Detected by mammographic screening | ||||||
| BMI | ||||||
| <25 | 56/612 | 1.0 | 1.0 | Ref. | 1.0 | Ref. |
| 25–30 | 52/548 | 1.1 | 1.0 | 0.7, 1.5 | 0.9 | 0.6, 1.4 |
| >30 | 29/209 | 1.7 | 1.5 | 0.9, 2.3 | 1.0 | 0.6, 1.6 |
| Not detected by mammographic screening | ||||||
| BMI | ||||||
| <25 | 104/466 | 2.8 | 1.0 | Ref. | 1.0 | Ref. |
| 25–30 | 74/321 | 2.9 | 1.1 | 0.8, 1.5 | 0.9 | 0.7, 1.3 |
| >30 | 36/112 | 4.6 | 1.6 | 1.1, 2.4 | 1.4 | 0.9, 2.1 |
BMI=body mass index (kg m−2); CI=confidence interval; HR=hazard ratio; HRT=hormone replacement therapy.
a
Breast cancer deaths per 100 person-years.
b
Adjusted for age at diagnosis in 5-year categories, and current alcohol intake (0, 0–4.9, 5–9.9, and ⩾10 g day−1).
c
Adjusted for age at diagnosis, current alcohol intake (0, 0–4.9, 5–9.9, and ⩾10 g day−1), tumour size (⩽2, >2 cm), and lymph node positivity (no, yes).