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. Author manuscript; available in PMC: 2015 Oct 2.
Published in final edited form as: Int J Cancer. 2013 Dec 18;135(1):186–195. doi: 10.1002/ijc.28644

Table 3. Reproductive ages and intervals and breast cancer risk, by ER/PR status; the Shanghai Breast Cancer Study.

Risk Factors Controls(n=3341) ER / PR Status Phomogeneity c
ER + / PR + ER + / PR- Or ER - / PR + ER - / PR-
Cases(n=1412) OR 1, 2 P Cases(n=544) OR 1, 2 P Cases(n=748) OR 1, 2 P
Ages at:
First Pregnancy (years) a
 <25 1246 425 1 (reference) 1 - 165 1 (reference) 1 - 270 1 (reference) 1 -
 25-29 1721 777 1.07 (0.91-1.26) 0.407 311 1.15 (0.91-1.45) 0.236 372 0.84 (0.69-1.02) 0.075
 30-34 326 182 1.25 (0.99-1.59) 0.060 59 1.12 (0.79-1.59) 0.535 89 1.00 (0.74-1.34) 0.995
 >=35 48 28 1.46 (0.88-2.40) 0.141 9 1.19 (0.56-2.54) 0.648 17 1.31 (0.73-2.37) 0.365
 P trend 0.035 0.379 0.995 0.132
First Live Birth (years) a
 <25 914 292 1 (reference) 1 - 113 1 (reference) 1 - 185 1 (reference) 1 -
 25-29 1878 811 1.06 (0.88-1.28) 0.536 318 1.14 (0.86-1.51) 0.352 414 0.91 (0.72-1.14) 0.395
 30-34 467 260 1.27 (1.00-1.61) 0.050 95 1.31 (0.93-1.85) 0.124 122 1.01 (0.75-1.36) 0.962
 >=35 82 49 1.53 (1.02-2.29) 0.042 18 1.46 (0.81-2.63) 0.207 27 1.32 (0.80-2.16) 0.279
 P trend 0.009 0.080 0.447 0.206
Last Pregnancy (years) a
 <30 1267 461 1 (reference) 1 - 167 1 (reference) 1 - 262 1 (reference) 1 -
 30-34 918 398 1.05 (0.91-1.22) 0.514 172 1.27 (1.03-1.57) 0.026 199 0.99 (0.82-1.20) 0.918
 >=35 507 236 1.09 (0.91-1.30) 0.370 92 1.20 (0.93-1.56) 0.167 135 1.20 (0.96-1.50) 0.115
 P trend 0.183 0.049 0.199 0.704
Last Live Birth (years) b
 <30 722 223 1 (reference) 1 - 90 1 (reference) 1 - 135 1 (reference) 1 -
 30-34 269 93 0.95 (0.72-1.25) 0.728 46 1.18 (0.81-1.71) 0.389 56 1.01 (0.73-1.41) 0.933
 >=35 64 24 0.86 (0.52-1.42) 0.556 8 0.73 (0.33-1.57) 0.417 17 1.22 (0.69-2.15) 0.496
 P trend 0.920 0.744 0.540 0.937
Intervals from:
Menarche to First live birth (years) a
 <10 953 291 1 (reference) 2 - 115 1 (reference) 2 - 187 1 (reference) 2 -
 10-14 1612 697 1.12 (0.93-1.34) 0.254 266 1.11 (0.84-1.45) 0.464 350 0.93 (0.74-1.16) 0.503
 >=15 775 423 1.31(1.06-1.62) 0.012 162 1.35 (0.99-1.83) 0.055 211 1.11 (0.86-1.44) 0.435
 P trend 0.008 0.035 0.31 0.151
Menarche to Last live birth (years) b
 <10 223 40 1 (reference) 2 - 19 1 (reference) 2 - 32 1 (reference) 2 -
 10-14 485 162 1.17 (0.89-1.54) 0.268 58 1.06 (0.70-1.59) 0.796 100 1.23 (0.88-1.72) 0.217
 >=15 347 138 1.12 (0.84-1.49) 0.432 67 1.39 (0.94-2.06) 0.102 76 1.11 (0.78-1.57) 0.567
 P trend 0.018 0.066 0.426 0.238
First to Second Live Birth (years) b
 <1.5 112 54 1 (reference) 1 - 11 1 (reference) 1 - 18 1 (reference) 1 -
 1.5-2.99 517 162 0.83 (0.62-1.11) 0.201 69 1.33 (0.85-2.07) 0.211 90 1.02 (0.70-1.48) 0.934
 >=3 422 123 0.67 (0.51-0.88) 0.004 64 1.14 (0.78-1.68) 0.499 100 1.20 (0.88-1.65) 0.254
 P trend 0.013 0.679 0.104 0.002
First to Last Pregnancy (years) a
 <3 877 418 1 (reference) 1 - 137 1 (reference) 1 - 212 1 (reference) 1 -
 3-4.99 573 195 0.75 (0.62-0.92) 0.004 87 1.00(0.76-1.31) 0.991 106 0.80(0.63-1.03) 0.082
 5-9.99 826 326 0.95 (0.80-1.13) 0.587 138 1.25 (0.97-1.60) 0.083 180 1.03 (0.82-1.28) 0.814
 >=10 410 151 0.89 (0.71-1.11) 0.304 67 1.23 (0.90-1.68) 0.199 94 1.10 (0.83-1.44) 0.509
 P trend 0.474 0.053 0.485 0.112
First to Last Live Birth (years) b
 <3 344 130 1 (reference) 1 - 46 1 (reference) 1 - 66 1 (reference) 1 -
 3-4.99 298 86 0.72 (0.53-0.99) 0.043 38 1.00 (0.64-1.55) 0.983 53 1.02 (0.70-1.48) 0.938
 5-9.99 348 103 0.85 (0.60-1.19) 0.334 54 1.44 (0.91-2.29) 0.118 75 1.39 (0.94-2.07) 0.099
 >=10 63 20 0.89 (0.49-1.61) 0.690 6 0.89 (0.35-2.27) 0.800 14 1.57 (0.79-3.13) 0.199
 P trend 0.556 0.364 0.071 0.212
a

Among Parous Women

b

Among Multiparous Women

c

Test for homogeneity of P-trend values among the hormone receptor groups, calculated using multivariable logistic regression

1

Adjusted for study phase, age, education, age at menarche, menopausal status, number of live birth, duration of breastfeeding, body mass index (BMI), physical activities in recent 10 years (Y/N), family history of breast cancer in first degree relative (Y/N), history of fibroadenoma (Y/N) and hormone replacement therapy (HRT) use (Y/N).

2

Adjusted for above except variable which is beginning or ending of the intervals