From: Epidemiology of breast cancer subtypes in two prospective cohort studies of breast cancer survivors
 | Luminal A (comparison) | Triple negativea | HER2-overexpressinga | ||||
---|---|---|---|---|---|---|---|
 | n | n | OR | 95% CI | n | OR | 95% CI |
Age at diagnosis (years) | Â | Â | Â | Â | Â | Â | Â |
   ≥ 65 (Ref) | 637 | 68 | Ref | --- | 23 | Ref | --- |
   50 to 64 | 871 | 115 | 1.99 | 0.85, 1.62 | 45 | 1.39 | 0.83, 2.32 |
   < 50 | 355 | 105 | 2.78 | 1.99, 3.90 | 25 | 1.75 | 0.97, 3.15 |
   Test for trend |  |  |  | P ≤ 0.0001 |  |  | P = 0.03 |
Race/ethnicity | Â | Â | Â | Â | Â | Â | Â |
   White (Ref) | 1464 | 204 | Ref | --- | 60 | Ref | --- |
   African American | 92 | 44 | 3.14 | 2.12, 4.66 | 5 | 1.25 | 0.49, 3.21 |
   Hispanic | 135 | 21 | 0.93 | 0.57, 1.53 | 13 | 2.19 | 1.16, 4.13 |
   Asian | 135 | 12 | 0.53 | 0.28, 0.97 | 12 | 2.02 | 1.05, 3.88 |
   Other | 37 | 7 | 1.28 | 0.56, 2.94 | 3 | 1.95 | 0.58, 6.52 |
Menopausal status | Â | Â | Â | Â | Â | Â | Â |
   Postmenopausal (Ref) | 1283 | 163 | Ref | --- | 57 | Ref | --- |
   Premenopausal | 406 | 91 | 0.84 | 0.55, 1.27 | 21 | 0.65 | 0.31, 1.33 |
Family history | Â | Â | Â | Â | Â | Â | Â |
   No (Ref) | 1453 | 229 | Ref | --- | 80 | Ref | --- |
   Yes | 410 | 59 | 0.95 | 0.69, 1.29 | 13 | 0.62 | 0.34, 1.13 |
Age at first full-term pregnancy (years) | Â | Â | Â | Â | Â | Â | Â |
   Nulliparous (Ref) | 335 | 52 | Ref | --- | 13 | Ref | --- |
   < 26 | 959 | 163 | 1.28 | 0.90, 1.82 | 61 | 2.02 | 1.07, 3.80 |
   ≥ 26 | 567 | 72 | 0.93 | 0.63, 1.38 | 18 | 0.86 | 0.42, 1.79 |
Parity | Â | Â | Â | Â | Â | Â | Â |
   Nulliparous (Ref) | 335 | 52 | Ref | --- | 13 | Ref | --- |
   1 to 2 children | 837 | 137 | 1.11 | 0.78, 1.58 | 40 | 1.30 | 0.68, 2.47 |
   ≥ 3 children | 691 | 99 | 1.18 | 0.81, 1.72 | 40 | 1.82 | 0.94, 3.53 |
Lifetime duration of breastfeeding | Â | Â | Â | Â | Â | Â | Â |
   Never (Ref) | 871 | 148 | Ref | --- | 43 | Ref | --- |
   0 to 3 months | 255 | 41 | 1.04 | 0.71, 1.52 | 16 | 1.29 | 0.71, 2.35 |
   ≥ 4 months | 711 | 97 | 0.78 | 0.59, 1.03 | 32 | 0.86 | 0.54, 1.38 |
Parity among never breastfedb | Â | Â | Â | Â | Â | Â | Â |
   Nulliparous (Ref) | 321 | 50 | Ref | --- | 12 | Ref | --- |
   1 to 2 children | 326 | 59 | 1.34 | (0.87, 2.08) | 15 | 1.52 | (0.68, 3.41) |
   ≥ 3 children | 224 | 39 | 1.68 | (1.00, 2.81) | 16 | 3.03 | (1.27, 7.23) |
Parity among 0 to 3 months breastfedb | Â | Â | Â | Â | Â | Â | Â |
   1 to 2 children (Ref) | 144 | 25 | Ref | --- | 9 | Ref | --- |
   ≥ 3 children | 108 | 16 | 1.16 | (0.53, 2.56) | 7 | 1.82 | (0.57, 5.80) |
Parity among ≥ 4 months breastfedb |  |  |  |  |  |  |  |
   1 to 2 children (Ref) | 358 | 52 | Ref | --- | 14 | Ref | --- |
   ≥ 3 children | 352 | 44 | 0.99 | (0.63, 1.55) | 17 | 1.23 | (0.57, 2.66) |
Alcohol use | Â | Â | Â | Â | Â | Â | Â |
   Never (Ref) | 709 | 110 | Ref | --- | 39 | Ref | --- |
   Ever | 880 | 129 | 0.98 | 0.73, 1.30 | 40 | 0.94 | 0.59, 1.50 |
Smoking history | Â | Â | Â | Â | Â | Â | Â |
   Never (Ref) | 921 | 146 | Ref | --- | 51 | Ref | --- |
   ≤ 10 | 251 | 41 | 0.95 | 0.65, 1.40 | 7 | 0.51 | 0.23, 1.14 |
   11 to 19 | 147 | 21 | 0.89 | 0.54, 1.47 | 8 | 1.17 | 0.54, 2.56 |
   ≥ 20 | 531 | 78 | 0.98 | 0.72, 1.34 | 26 | 1.05 | 0.63, 1.73 |
Hormone replacement therapy (postmenopausal only) | Â | Â | Â | Â | Â | Â | Â |
   Never (Ref) | 314 | 50 | Ref | --- | 24 | Ref | --- |
   Ever | 943 | 112 | 0.83 | 0.57, 1.20 | 33 | 0.45 | 0.26, 0.79 |
Oral contraceptive use | Â | Â | Â | Â | Â | Â | Â |
   Never (Ref) | 647 | 80 | Ref | --- | 29 | Ref | --- |
   Ever | 1160 | 202 | 0.97 | 0.72, 1.31 | 63 | 1.12 | 0.69, 1.83 |
BMI (kg/m2)c | Â | Â | Â | Â | Â | Â | Â |
   < 25 (Ref) | 785 | 110 | Ref | --- | 39 | Ref | --- |
   25 to 29 | 563 | 99 | 1.33 | 0.98, 1.81 | 31 | 1.21 | 0.74, 1.99 |
   ≥ 30 | 500 | 77 | 1.04 | 0.75, 1.45 | 23 | 1.03 | 0.59, 1.78 |
BMI (kg/m2) among premenopausalb | Â | Â | Â | Â | Â | Â | Â |
   < 25 (Ref) | 223 | 39 | Ref | --- | 7 | Ref | --- |
   25 to 29 | 99 | 28 | 1.82 | 1.03, 3.24 | 7 | 2.15 | 0.70, 6.58 |
   ≥ 30 | 81 | 23 | 1.97 | 1.03, 3.77 | 7 | 2.51 | 0.74, 8.51 |
BMI (kg/m2) among postmenopausalb | Â | Â | Â | Â | Â | Â | Â |
   < 25 (Ref) | 480 | 59 | Ref | --- | 25 | Ref | --- |
   25 to 29 | 422 | 60 | 1.08 | 0.73, 1.59 | 18 | 0.86 | 0.46, 1.61 |
   ≥ 30 | 372 | 43 | 0.76 | 0.49, 1.17 | 14 | 0.76 | 0.38, 1.51 |