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Table 3 Adjusted odds ratios (OR) and 95% confidence intervals (CI) for association between breast cancer subtypes and oral contraceptives and hormone therapy

From: Parity, hormones and breast cancer subtypes - results from a large nested case-control study in a national screening program

  Luminal A-like Luminal B-like HER2-negative Luminal B-like HER2-positive HER2-positive Triple-negative
ER+ PR+ HER2- ER+ PR- HER2- ER+ PR+/PR- HER2+ ER- PR- HER2+ ER- PR- HER2-
Controls (n) Cases (n) OR* 95% CI Controls (n) Cases (n) OR 95% CI Controls (n) Cases (n) OR 95% CI Controls (n) Cases (n) OR 95% CI Controls (n) Cases (n) OR 95% CI
Age at start of oral contraceptives (years)
 14–18 1476 285 1 Reference 334 65 1 Reference 187 45 1 Reference 128 17 1 Reference 180 55 1 Reference
 19–20 1462 387 1.33 (1.11, 1.59) 367 87 1.20 (0.82, 1.75) 230 49 0.90 (0.55, 1.45) 133 27 1.52 (0.75, 3.10) 206 46 0.67 (0.42, 1.07)
 21–24 1959 405 1.05 (0.87, 1.25) 458 92 1.04 (0.71, 1.53) 295 45 0.62 (0.37, 1.02) 130 24 1.45 (0.69, 3.04) 253 41 0.44 (0.27, 0.74)
 25–50 1993 397 0.99 (0.83, 1.20) 536 102 0.97 (0.66, 1.43) 296 58 0.80 (0.49, 1.32) 114 27 2.23 (1.06, 4.71) 258 58 0.63 (0.39, 1.03)
 Never used 6715 1344 1.01 (0.86, 1.19) 1758 363 0.99 (0.71, 1.38) 876 180 0.82 (0.53, 1.27) 501 115 2.05 (1.08, 3.89) 860 165 0.54 (0.36, 0.81)
p-trenda    0.09     0.43     0.71     0.02     0.03  
p-heterogeneity#        0.60     0.52     0.07     0.02  
Duration of oral contraceptives (years)
 Never used 6715 1344 1 Reference 1758 363 1 Reference 876 180 1 Reference 501 115 1 Reference 860 165 1 Reference
 <2 1839 364 0.97 (0.85, 1.11) 482 80 0.82 (0.62, 1.08) 275 34 0.64 (0.42, 0.97) 151 18 0.47 (0.27, 0.81) 263 43 0.85 (0.58, 1.26)
 2–5 1753 361 1.03 (0.90, 1.18) 435 88 1.01 (0.77, 1.33) 233 48 0.94 (0.64, 1.37) 113 17 0.61 (0.34, 1.09) 228 56 1.32 (0.92, 1.89)
 6–10 1568 332 1.06 (0.92, 1.23) 388 80 1.03 (0.77, 1.37) 240 56 1.23 (0.85, 1.76) 121 35 1.07 (0.66, 1.73) 203 47 1.20 (0.82, 1.76)
 >10 1266 298 1.11 (0.96, 1.29) 271 62 1.12 (0.81, 1.54) 204 45 0.95 (0.64, 1.42) 82 19 1.02 (0.56, 1.86) 149 38 1.25 (0.82, 1.90)
p-trend*    0.13     0.51     0.57     0.91     0.11  
p-heterogeneity#        0.61     0.10     0.003     0.56  
Age at start of intrauterine device (years)
 14–28 612 125 1 Reference 152 28 1 Reference 82 14 1 Reference 55 12 1 Reference 88 19 1 Reference
 29–35 681 143 0.97 (0.73, 1.28) 152 39 1.31 (0.75, 2.30) 93 10 0.76 (0.30, 1.90) 46 7 0.74 (0.24, 2.25) 78 25 1.42 (0.70, 2.88)
 36–42 532 147 1.33 (1.00, 1.77) 114 21 0.83 (0.43, 1.58) 89 19 1.34 (0.60, 3.01) 43 7 0.75 (0.26, 2.16) 78 12 0.70 (0.31, 1.58)
 43 − 50 456 121 1.16 (0.86, 1.56) 136 25 0.86 (0.46, 1.59) 70 11 1.06 (0.42, 2.70) 39 7 0.94 (0.32, 2.78) 70 14 0.94 (0.42, 2.12)
 Never used 10000 2025 0.93 (0.75, 1.15) 2600 529 0.94 (0.61, 1.45) 1368 284 1.36 (0.72, 2.56) 729 153 1.10 (0.56, 2.16) 1279 267 0.94 (0.55, 1.61)
p-trenda    0.07     0.34     0.10     0.40     0.45  
p-heterogeneity#        0.22     0.12     0.20     0.38  
Duration of intrauterine device (years)
 Never used 10000 2025 1 Reference 2600 529 1 Reference 1368 284 1 Reference 729 153 1 Reference 1279 267 1 Reference
 <2 341 64 0.91 (0.69, 1.21) 83 16 0.86 (0.49, 1.52) 56 13 1.23 (0.62, 2.43) 33 5 0.84 (0.31, 2.32) 37 7 0.90 (0.38, 2.13)
 2–5 432 104 1.17 (0.93, 1.48) 112 21 0.95 (0.58, 1.56) 62 11 0.96 (0.47, 1.94) 36 7 0.81 (0.34, 1.91) 57 21 1.79 (1.01, 3.16)
 6–10 615 140 1.16 (0.95, 1.42) 153 40 1.37 (0.94, 2.01) 89 15 0.86 (0.46, 1.59) 53 8 0.62 (0.27, 1.43) 99 20 1.23 (0.72, 2.11)
 >10 820 212 1.35 (1.14, 1.61) 176 31 0.96 (0.63, 1.46) 111 12 0.51 (0.27, 0.96) 63 12 0.73 (0.37, 1.47) 120 20 0.75 (0.44, 1.28)
p-trend    <0.0001     0.52     0.06     0.18     0.98  
p-heterogeneity#        0.08     0.01     0.65     0.22  
Hormone therapy use
 Never 7411 1356 1 Reference 1762 356 1 Reference 1010 195 1 Reference 573 113 1 Reference 991 196 1 Reference
 Past 4809 1086 1.27 (1.15, 1.40) 1361 276 0.98 (0.81, 1.18) 688 142 1.07 (0.81, 1.42) 319 65 0.88 (0.60, 1.30) 575 126 1.04 (0.79, 1.38)
 Estrogen current 655 131 1.06 (0.86, 1.31) 162 31 0.81 (0.53, 1.23) 85 19 1.14 (0.65, 1.99) 51 12 1.12 (0.54, 2.35) 93 16 0.79 (0.43, 1.46)
 Estrogen and progesterone current 345 184 2.92 (2.36, 3.62) 89 33 1.74 (1.10, 2.74) 48 18 1.67 (0.89, 3.14) 32 6 0.88 (0.33, 2.30) 49 10 0.92 (0.43, 1.98)
p-trend    <0.0001     0.34     0.15     0.77     0.72  
p-heterogeneity#        0.05     0.34     0.03     0.01  
Duration of hormone therapy (years)
 Never 7411 1356 1 Reference 1762 356 1 Reference 1010 195 1 Reference 573 113 1 Reference 991 196 1 Reference
  < =3 1625 306 1.09 (0.94, 1.26) 473 96 0.99 (0.76, 1.30) 237 43 0.90 (0.61, 1.34) 134 20 0.66 (0.38, 1.16) 234 41 0.77 (0.52, 1.15)
 4–8 1130 240 1.21 (1.03, 1.43) 289 64 1.06 (0.77, 1.46) 155 35 1.19 (0.76, 1.87) 76 19 1.18 (0.65, 2.13) 119 25 0.99 (0.59, 1.67)
 >8 1756 555 1.84 (1.61, 2.11) 485 112 1.24 (0.95, 1.61) 253 63 1.34 (0.91, 1.98) 108 23 0.93 (0.52, 1.65) 222 47 1.04 (0.69, 1.56)
p-trend    <0.0001     0.15     0.14     0.94     1.00  
p-heterogeneity#        0.001     0.48     0.11     0.02  
Duration of estrogen and progesterone therapy (years)
 Never 7411 1356 1 Reference 1762 356 1 Reference 1010 195 1 Reference 573 113 1 Reference 991 196 1 Reference
  < =5 1908 412 1.25 (1.09, 1.43) 545 114 1.02 (0.79, 1.32) 276 45 0.79 (0.53, 1.17) 153 30 0.92 (0.56, 1.53) 230 54 1.19 (0.81, 1.74)
  > 5 1796 561 1.80 (1.58, 2.06) 496 116 1.18 (0.90, 1.54) 256 71 1.47 (1.00, 2.16) 105 29 1.04 (0.62, 1.74) 211 52 1.34 (0.89, 2.02)
p-trend    <0.0001     0.31     0.27     0.98     0.13  
p-heterogeneity#        0.004     0.19     0.19     0.02  
  1. aThe category Never was not included in the analysis of p-trend. *p for trend and OR mutually adjusted for age (50–54, 55–59, 60–64, 65–70 years at screening), body mass index (BMI) (≤22, 23–25, 26–28, >28 at screening), education (no education/primary school, high school, bachelor or master’s degree), age at menarche (9–12, 13, 14, 15–18 years), number of pregnancies (0, 1, 2, 3, ≥4), menopausal status (premenopausal, perimenopausal, postmenopausal). # p for heterogeneity across subtypes was determined in a case − case model (see “Methods”). ER estrogen receptor, PR progesterone receptor, HER2 human epidermal growth factor receptor 2