Table 2.
Case-only ORs comparing basal-like, HER2+/ER−, luminal B and unclassified to luminal A breast cancer
| Risk factor | Luminal A | Basal-like
|
HER2+/ER−
|
Luminal B
|
Unclassified
|
||||
|---|---|---|---|---|---|---|---|---|---|
| N | N | OR (95% CI) | N | OR (95% CI) | N | OR (95% CI) | N | OR (95% CI) | |
| Agea | |||||||||
| ≥60 | 259 | 35 | Referent | 27 | Referent | 37 | Referent | 37 | Referent |
| 50–59 | 181 | 46 | 1.8 (1.1–2.8) | 29 | 1.5 (0.8–2.6) | 28 | 1.1 (0.6–1.9) | 25 | 0.9 (0.5–1.6) |
| 40–49 | 267 | 89 | 2.6 (1.7–3.9) | 39 | 1.4 (0.8–2.4) | 50 | 1.3 (0.8–2.1) | 59 | 1.6 (1.0–2.5) |
| <40 | 89 | 55 | 4.5 (2.7–7.3) | 21 | 2.3 (1.2–4.2) | 22 | 1.7 (1.0–3.1) | 29 | 2.2 (1.3–3.9) |
| Trend test | P < 0.0001 | P = 0.02 | P = 0.06 | P = 0.001 | |||||
| Raceb | |||||||||
| White | 509 | 103 | Referent | 68 | Referent | 92 | Referent | 71 | Referent |
| African-American | 287 | 122 | 2.1 (1.6–2.9) | 48 | 1.3 (0.8–1.9) | 45 | 0.9 (0.6–1.3) | 79 | 2.0 (1.4–2.8) |
| Menopausal statusc | |||||||||
| Postmenopausal | 472 | 101 | Referent | 70 | Referent | 72 | Referent | 71 | Referent |
| Premenopausal | 324 | 124 | 0.8 (0.5–1.3) | 46 | 0.4 (0.3–0.8) | 65 | 1.0 (0.6–1.7) | 79 | 1.1 (0.6–1.9) |
| Family historyc | |||||||||
| No | 640 | 186 | Referent | 95 | Referent | 111 | Referent | 119 | Referent |
| Yes | 130 | 36 | 1.0 (0.7–1.5) | 17 | 0.9 (0.5–1.6) | 25 | 1.1 (0.7–1.8) | 24 | 1.0 (0.6–1.7) |
| Age at menarchec | |||||||||
| ≥13 | 406 | 100 | Referent | 58 | Referent | 71 | Referent | 61 | Referent |
| <13 | 389 | 125 | 1.3 (0.9–1.7) | 58 | 1.0 (0.7–1.5) | 66 | 0.9 (0.7–1.4) | 88 | 1.5 (1.0–2.1) |
| Parityc | |||||||||
| Nulliparous | 132 | 26 | Referent | 23 | Referent | 19 | Referent | 19 | Referent |
| 1–2 children | 381 | 117 | 1.6 (1.0–2.7) | 51 | 0.8 (0.5–1.3) | 73 | 1.3 (0.8–2.3) | 70 | 1.3 (0.8–2.3) |
| ≥3 | 283 | 82 | 1.7 (1.0–2.9) | 42 | 1.0 (0.5–1.7) | 45 | 1.3 (0.7–2.3) | 61 | 1.7 (1.0–3.0) |
| Age at first full-term pregnancy (AFFTP)c | |||||||||
| Nulliparous | 132 | 26 | Referent | 23 | Referent | 19 | Referent | 19 | Referent |
| <26 | 477 | 159 | 1.9 (1.2–3.0) | 70 | 0.8 (0.5–1.5) | 77 | 1.2 (0.7–2.1) | 96 | 1.5 (0.9–2.5) |
| ≥26 | 184 | 39 | 1.2 (0.7–2.1) | 22 | 0.7 (0.4–1.3) | 41 | 1.6 (0.9–2.8) | 35 | 1.5 (0.8–2.7) |
| Lifetime duration lactationc | |||||||||
| Never | 500 | 158 | Referent | 76 | Referent | 87 | Referent | 100 | Referent |
| >0–3 months | 92 | 27 | 1.1 (0.7–1.9) | 14 | 1.1 (0.6–2.0) | 17 | 1.1 (0.6–1.9) | 11 | 0.7 (0.4–1.4) |
| 4+ | 204 | 40 | 0.7 (0.5–1.1) | 26 | 0.9 (0.6–1.5) | 33 | 1.0 (0.6–1.5) | 39 | 1.1 (0.7–1.7) |
| Alcohol usec | |||||||||
| Never | 240 | 70 | Referent | 35 | Referent | 30 | Referent | 62 | Referent |
| Ever | 556 | 154 | 0.9 (0.6–1.2) | 81 | 1.0 (0.6–1.5) | 107 | 1.4 (0.9–2.2) | 88 | 0.6 (0.4–0.9) |
| Smoking durationc | |||||||||
| Never smoker | 408 | 126 | Referent | 66 | Referent | 66 | Referent | 94 | Referent |
| <10 years | 94 | 31 | 0.9 (0.6–1.5) | 14 | 0.9 (0.5–1.6) | 18 | 1.1 (0.6–1.9) | 17 | 0.8 (0.4–1.3) |
| 11–19 | 90 | 31 | 1.1 (0.7–1.7) | 11 | 0.7 (0.4–1.4) | 15 | 1.0 (0.5–1.8) | 10 | 0.5 (0.2–1.0) |
| ≥20 | 201 | 37 | 0.7 (0.5–1.1) | 25 | 0.8 (0.5–1.4) | 37 | 1.2 (0.8–1.9) | 29 | 0.7 (0.5–1.2) |
| Oral contraceptive usec | |||||||||
| Never | 286 | 66 | Referent | 35 | Referent | 44 | Referent | 50 | Referent |
| Ever | 507 | 158 | 0.9 (0.6–1.3) | 80 | 1.1 (0.6–1.7) | 93 | 0.9 (0.6–1.5) | 99 | 0.8 (0.5–1.3) |
| Hormone replacement therapy (postmenopausal women only)c | |||||||||
| Never | 247 | 60 | Referent | 32 | Referent | 29 | Referent | 35 | Referent |
| Ever | 225 | 41 | 0.8 (0.5–1.3) | 38 | 1.2 (0.7–2.1) | 43 | 1.6 (0.9–2.8) | 36 | 1.4 (0.8–2.4) |
| BMI (kg/m2)c | |||||||||
| Overall | |||||||||
| <25 | 288 | 64 | Referent | 41 | Referent | 59 | Referent | 60 | Referent |
| 25–29 | 208 | 66 | 1.4 (1.0–2.2) | 36 | 1.2 (0.8–2.0) | 39 | 1.0 (0.6–1.5) | 26 | 0.6 (0.3–0.9) |
| ≥30 | 277 | 88 | 1.3 (0.8–1.9) | 36 | 0.9 (0.5–1.5) | 38 | 0.7 (0.4–1.1) | 59 | 0.8 (0.5–1.2) |
| Premenopausal | |||||||||
| <25 | 138 | 34 | Referent | 20 | Referent | 29 | Referent | 31 | Referent |
| 25–29 | 75 | 35 | 1.7 (1.0–3.1) | 13 | 1.1 (0.5–2.3) | 22 | 1.4 (0.8–2.7) | 13 | 0.7 (0.3–1.5) |
| ≥30 | 105 | 50 | 1.6 (0.9–2.7) | 12 | 0.6 (0.3–1.5) | 14 | 0.7 (0.3–1.4) | 32 | 1.1 (0.6–2.0) |
| Postmenopausal | |||||||||
| <25 | 150 | 30 | Referent | 21 | Referent | 30 | Referent | 29 | Referent |
| 25–29 | 133 | 31 | 1.2 (0.7–3.0) | 23 | 1.3 (0.7–2.5) | 17 | 0.6 (0.3–1.2) | 13 | 0.5 (0.2–0.9) |
| ≥30 | 172 | 38 | 1.0 (0.5–1.7) | 24 | 1.1 (0.6–2.2) | 24 | 0.7 (0.4–1.3) | 27 | 0.6 (0.3–1.1) |
| WHRc | |||||||||
| Overall | |||||||||
| <0.77 | 210 | 40 | Referent | 38 | Referent | 53 | Referent | 36 | Referent |
| 0.77–0.83 | 268 | 89 | 2.0 (1.3–3.0) | 42 | 0.9 (0.5–1.5) | 38 | 0.6 (0.4–1.0) | 40 | 0.9 (0.5–1.5) |
| ≥0.84 | 306 | 91 | 1.7 (1.1–2.8) | 35 | 0.6 (0.4–1.1) | 44 | 0.6 (0.4–1.0) | 71 | 1.3 (0.8–2.1) |
| Premenopausal | |||||||||
| <0.77 | 122 | 25 | Referent | 16 | Referent | 29 | Referent | 25 | Referent |
| 0.77–0.83 | 113 | 56 | 2.3 (1.3–4.1) | 18 | 1.2 (0.6–2.6) | 18 | 0.7 (0.4–1.3) | 23 | 1.0 (0.5–1.8) |
| ≥0.84 | 86 | 41 | 1.9 (1.0–3.6) | 11 | 0.9 (0.4–2.2) | 17 | 0.9 (0.4–1.8) | 28 | 1.4 (0.7–2.7) |
| Postmenopausal | |||||||||
| <0.77 | 88 | 15 | Referent | 22 | Referent | 24 | Referent | 11 | Referent |
| 0.77–0.83 | 155 | 33 | 1.4 (0.7–2.8) | 24 | 0.7 (0.4–1.4) | 20 | 0.5 (0.3–1.0) | 17 | 0.8 (0.4–1.9) |
| ≥0.84 | 220 | 50 | 1.4 (0.7–2.7) | 24 | 0.5 (0.3–1.0) | 17 | 0.5 (0.2–0.9) | 43 | 1.3 (0.6–2.7) |
a
Adjusted for race
b
Adjusted for age
c
Adjusted for age and race