Table 3.
Various breast cancer risk factors and risk of ductal, lobular and tubular breast cancer
| Controls | Ductal cancer | Lobular cancer | Tubular cancer | ||||
| No. | No. | ORa (95%CI) | ORa (95%CI) | No. | ORa (95%CI) | ||
| Factor | |||||||
| Parous | |||||||
| Nulliparous | 337 | 292 | 1.0 (Ref) | 40 | 1.0 (Ref) | 10 | 1.0 (Ref) |
| Parous | 2,643 | 1,561 | 0.7 (0.6–0.8) | 258 | 0.8 (0.6–1.2) | 81 | 1.0 (0.5–2.0) |
| No of birthsb | |||||||
| 1 | 558 | 416 | 1.0 (Ref) | 47 | 1.0 (Ref) | 21 | 1.0 (Ref) |
| 2 | 1073 | 690 | 0.9 (0.7–1.0) | 126 | 1.5c (1.0–2.1) | 36 | 0.9 (0.5–1.6) |
| 3 | 630 | 318 | 0.7 (0.6–0.9) | 58 | 1.3c (0.8–1.9) | 19 | 0.9 (0.5–1.8) |
| ≥4 | 382 | 137 | 0.6 (0.4–0.7) | 27 | 1.1c (0.7–1.9) | 5 | 0.5 (0.2–1.3) |
| Age at first birth (years)b | |||||||
| <20 | 305 | 143 | 0.9 (0.7–1.1) | 20 | 0.7 (0.4–1.1) | 9 | 1.3 (0.6–2.9) |
| 20–24 | 1,125 | 600 | 1.0 (Ref) | 106 | 1.0 (Ref) | 25 | 1.0 (Ref) |
| 25–29 | 836 | 526 | 1.1 (1.0–1.3) | 79 | 1.0 (0.7–1.4) | 29 | 1.5 (0.9–2.6) |
| ≥30 | 377 | 292 | 1.3 (1.1–1.6) | 53 | 1.6 (1.1–2.3) | 18 | 1.9 (1.0–3.7) |
| Age at menarche (years)d | |||||||
| <12 | 164 | 134 | 1.3 (1.0–1.7) | 23 | 1.3 (0.8–2.1) | 4 | 0.7 (0.2–1.9) |
| 12–13 | 1,155 | 702 | 1.0 (Ref) | 117 | 1.0 (Ref) | 38 | 1.0 (Ref) |
| 14–15 | 1,161 | 723 | 1.1 (0.9–1.2) | 109 | 1.0 (0.7–1.3) | 43 | 1.2 (0.7–1.8) |
| ≥16 | 236 | 113 | 0.8 (0.6–1.0) | 23 | 1.0 (0.6–1.5) | 3 | 0.4 (0.1–1.2) |
| Age at menopause (years)e | |||||||
| <45 | 328 | 144 | 0.7 (0.5–0.8) | 22 | 0.7 (0.4–1.1) | 4 | 0.4 (0.1–1.1) |
| 45–49 | 658 | 368 | 0.8 (0.7–1.0) | 68 | 1.0 (0.8–1.4) | 24 | 1.2 (0.7–2.0) |
| 50–54 | 1,236 | 805 | 1.0 (Ref) | 121 | 1.0 (Ref) | 37 | 1.0 (Ref) |
| ≥55 | 268 | 174 | 1.0 (0.8–1.3) | 27 | 1.1 (0.7–1.7) | 3 | 0.4 (0.1–1.2) |
| Height (cm) | |||||||
| <160 | 652 | 361 | 1.0 (Ref) | 46 | 1.0 (Ref) | 16 | 1.0 (Ref) |
| 160–164 | 1,012 | 593 | 1.0 (0.9–1.2) | 110 | 1.5c (1.1–2.2) | 27 | 1.0 (0.5–1.8) |
| 165–169 | 880 | 555 | 1.1 (0.9–1.3) | 86 | 1.3 (0.9–1.9) | 27 | 1.1 (0.6–2.1) |
| ≥170 | 436 | 344 | 1.3 (1.1–1.6) | 57 | 1.7 (1.1–2.6) | 21 | 1.7 (0.9–3.3) |
| Recent BMI (kg/m2)f | |||||||
| <22.2 | 430 | 165 | 1.0 (Ref) | 26 | 1.0 (Ref) | 9 | 1.0 (Ref) |
| 22.2–<24.2 | 423 | 214 | 1.3 (1.0–1.7) | 25 | 1.0 (0.6–1.7) | 10 | 1.1 (0.4–2.8) |
| 24.2–<26.0 | 427 | 217 | 1.3 (1.0–1.7) | 21 | 0.8 (0.5–1.5) | 9 | 1.0 (0.4–2.5) |
| 26.0–<28.5 | 420 | 251 | 1.6 (1.2–2.0) | 39 | 1.6 (0.9–2.6) | 9 | 1.0 (0.4–2.6) |
| ≥28..5 | 430 | 301 | 1.9 (1.5–2.3) | 41 | 1.6 (1.0–2.6) | 9 | 1.0 (0.4–2.6) |
| Adult weight gain (kg)d,f,g | |||||||
| <0 | 159 | 64 | 0.8 (0.6–1.1) | 11 | 0.9 (0.5–1.9) | 4 | 0.8 (0.3–2.4) |
| 0–9.5 | 459 | 242 | 1.0 (Ref) | 34 | 1.0 (Ref) | 15 | 1.0 (Ref) |
| 10–19.5 | 534 | 349 | 1.2 (1.0–1.5) | 44 | 1.1 (0.7–1.8) | 13 | 0.7 (0.3–1.6) |
| 20–29.5 | 226 | 171 | 1.5 (1.1–1.9) | 21 | 1.2 (0.7–2.2) | 6 | 0.8 (0.3–2.2) |
| ≥30 | 99 | 75 | 1.5 (1.1–2.1) | 13 | 1.8 (0.9–3.5) | 6 | 2.0 (0.7–5.3) |
| Mother or sister with breast cancerd | |||||||
| No | 2,294 | 1,530 | 1.0 (Ref) | 237 | 1.0 (Ref) | 73 | 1.0 (Ref) |
| Yes | 233 | 278 | 1.8 (1.5–2.2) | 57 | 2.4 (1.8–3.4) | 15 | 2.2 (1.2–3.9) |
| Operated due to benign breast diseased | |||||||
| No | 2,315 | 1,590 | 1.0 (Ref) | 245 | 1.0 (Ref) | 82 | 1.0 (Ref) |
| Yes | 242 | 253 | 1.5 (1.2–1.8) | 53 | 1.9 (1.4–2.6) | 9 | 0.9 (0.4–1.8) |
| Oral contraceptive used | |||||||
| No use | 2,030 | 1,237 | 1.0 (Ref) | 198 | 1.0 (Ref) | 55 | 1.0 (Ref) |
| Duration | |||||||
| <5 years | 470 | 302 | 0.9 (0.7–1.0) | 40 | 0.6 (0.4–0.9) | 23 | 1.3 (0.7–2.2) |
| ≥5 years | 331 | 215 | 0.9 (0.7–1.1) | 42 | 0.9 (0.6–1.4) | 13 | 1.0 (0.5–1.9) |
| Recent alcohol consumption (g/day)d | |||||||
| No alcohol | 1,108 | 762 | 1.0 (Ref) | 111 | 1.0 (Ref) | 28 | 1.0 (Ref) |
| <5 | 905 | 674 | 1.0 (0.9–1.2) | 101 | 1.0 (0.8–1.4) | 34 | 1.2 (0.7–2.1) |
| ≥5–10 | 210 | 171 | 1.1 (0.9–1.4) | 32 | 1.3 (0.9–2.1) | 12 | 1.8 (0.9–3.6) |
| >10 | 100 | 72 | 1.0 (0.7–1.4) | 19 | 1.6 (0.9–2.8) | 10 | 3.1c (1.4–6.8) |
| Recent smokingd | |||||||
| No | 2,212 | 1,442 | 1.0 (Ref) | 229 | 1.0 (Ref) | 63 | 1.0 (Ref) |
| Yes | 696 | 408 | 1.2 (1.0–1.4) | 68 | 1.1 (0.8–1.5) | 28 | 0.8c (0.5–1.2) |
Recent = one year before data collection. aAdjusted for age, and where applicable also for estrogen-progestin use (ever/never). bNumber of births and age at first birth were adjusted for each other. cStatistically significant difference compared with the estimate for ductal cancer. dSome cases and controls excluded due to missing information. eWomen with unknown age at menopause and women using menopausal hormone therapy apart from local estrogen before menopause excluded. fWomen ever menopausal hormone therapy apart from local estrogen excluded. gWeight gain from 18 years of age to one year before data collection. BMI, body mass index; CI, confidence interval; OR, odds ratio; Ref, reference category.