Table 3. Odds ratios (OR) and 95% confidence intervals (95% CI) of first myocardial infarction after breast cancer diagnosis associated with tumor and treatment characteristics.
| Characteristics | # of cases/# of controls | Univariate OR (95% CI) | Multivariatea OR (95% CI) |
|---|---|---|---|
| Stage at diagnosis | |||
| Localised | 89/183 | 1.0 (referent) | 1.0 (referent) |
| Regional | 38/73 | 1.1 (0.7–1.7) | 1.0 (0.6–1.8) |
| Distant/unstaged | 7/6 | 2.5 (0.8–8.0) | 2.2 (0.6–7.7) |
| Oestrogen receptor status | |||
| Negative | 20/45 | 1.0 (referent) | 1.0 (referent) |
| Positive or borderline | 86/154 | 1.3 (0.7–2.4) | 1.3 (0.6–2.6) |
| Not done | 28/63 | ||
| Progesterone receptor status | |||
| Negative | 33/73 | 1.0 (referent) | 1.0 (referent) |
| Positive or borderline | 61/110 | 1.3 (0.8–2.1) | 1.1 (0.6–1.9) |
| Not done | 40/79 | ||
| Lymph nodes involved | |||
| No | 75/155 | 1.0 (referent) | 1.0 (referent) |
| Yes | 37/71 | 1.1 (0.7–1.7) | 1.0 (0.6–1.9) |
| No nodal surgery | 22/36 | ||
| Tamoxifen therapy ever b | |||
| No | 65/132 | 1.0 (referent) | 1.0 (referent) |
| Yes | 69/130 | 1.1 (0.7–1.8) | 1.2 (0.7–1.9) |
| Duration of use (months) | |||
| None | 65/132 | 1.0 (referent) | 1.0 (referent) |
| <24 | 29/47 | 1.5 (0.8–2.9) | 1.6 (0.8–3.2) |
| ⩾24 | 35/79 | 0.9 (0.5–1.5) | 0.9 (0.5–1.7) |
| Unknown | 5/4 | ||
| Radiation therapy b | |||
| No | 101/223 | 1.0 (referent) | 1.0 (referent) |
| Yes | 33/39 | 1.8 (1.1–3.1) | 2.0 (1.1–3.5) |
| Radiation cumulative dose (rads)c | |||
| None | 101/223 | 1.0 (referent) | 1.0 (referent) |
| ⩽5000 | 18/18 | 2.1 (1.04–4.4) | 2.2 (1.01–4.8) |
| >5000 | 14/20 | 1.5 (0.7–3.1) | 1.7 (0.7–3.8) |
| Radiation side | |||
| None | 101/223 | 1.0 (referent) | 1.0 (referent) |
| Right | 13/14 | 2.0 (0.9–4.8) | 2.1 (0.8–5.3) |
| Left | 20/25 | 1.7 (0.9–3.2) | 1.9 (0.9–3.9) |
| Tamoxifen and radiation therapy | |||
| Neither | 52/120 | 1.0 (referent) | 1.0 (referent) |
| Radiation therapy only | 13/12 | 2.5 (1.02–5.9) | 2.9 (1.2–7.5) |
| Tamoxifen only | 49/103 | 1.2 (0.7–2.0) | 1.3 (0.8–2.3) |
| Both | 20/27 | 1.8 (0.9–3.6) | 2.0 (0.9–4.4) |
| Tamoxifen months of use and radiation therapy b | |||
| Neither | 52/120 | 1.0 (referent) | 1.0 (referent) |
| Radiation therapy only | 13/12 | 2.5 (1.04–6.1) | 2.9 (1.1–7.5) |
| No radiation therapy | |||
| Tamoxifen | |||
| <24 | 18/36 | 1.5 (0.7–3.0) | 1.7 (0.8–3.7) |
| ⩾24 | 26/64 | 1.0 (0.5–1.8) | 1.1 (0.6–2.1) |
| Radiation therapy | |||
| Tamoxifen | |||
| <24 | 11/11 | 2.4 (0.9–6.4) | 3.2 (1.1–9.1) |
| ⩾24 | 9/15 | 1.4 (0.5–3.7) | 1.4 (0.5–4.0) |
| Tamoxifen months unknown | 5/4 | ||
| Chemotherapy | |||
| No | 109/218 | 1.0 (referent) | 1.0 (referent) |
| Yes | 25/44 | 1.2 (0.6–2.1) | 1.2 (0.6–2.3) |
a
All multivariate models include categorical items for histories of hypertension and diabetes, smoking and a combined item for tamoxifen and radiation treatment.
b
In multivariate model, the combined tamoxifen-radiation therapy item was replaced by separate items. For example, the model to examine tamoxifen duration of use included the radiation therapy (yes/no) item.
c
Subjects with details unknown removed (one case with matched controls, one control).