Age and center stratified | Multivariable adjusted1 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
ER+PR+ | ER-PR- | ER+PR+ | ER-PR- | |||||||||
(n = 3567) | (n = 998) | (n = 3567) | (n = 998) | |||||||||
Reproductive factor | Cases | HR | 95% CI | Cases | HR | 95% CI | Cases | HR | 95% CI | Cases | HR | 95% CI |
Age at menarche | ||||||||||||
<13 years | 1373 | 1.00 | Reference | 376 | 1.00 | Reference | 1373 | 1.00 | Reference | 376 | 1.00 | Reference |
14 years | 1717 | 0.96 | (0.90-1.04) | 481 | 0.98 | (0.86-1.13) | 1717 | 0.96 | (0.89-1.03) | 481 | 0.97 | (0.85-1.12) |
≥15 years | 439 | 0.76 | (0.68-0.85) | 135 | 0.85 | (0.69-1.04) | 439 | 0.76 | (0.68-0.85) | 135 | 0.84 | (0.69-1.03) |
P for trend | <0.001 | 0.17 | <0.001 | 0.17 | ||||||||
Subtype heterogeneity2 | 0.44 | 0.48 | ||||||||||
Age at menopause 3 | ||||||||||||
≤48 years | 464 | 1.00 | Reference | 135 | 1.00 | Reference | 464 | 1.00 | Reference | 135 | 1.00 | Reference |
49–50 years | 397 | 1.10 | (0.95-1.26) | 116 | 1.09 | (0.84-1.41) | 397 | 1.12 | (0.98-1.29) | 116 | 1.09 | (0.84-1.42) |
51–54 years | 280 | 1.04 | (0.89-1.21) | 63 | 0.88 | (0.64-1.20) | 280 | 1.06 | (0.91-1.24) | 63 | 0.87 | (0.64-1.20) |
≥55 years | 121 | 1.19 | (0.97-1.47) | 32 | 1.06 | (0.71-1.58) | 121 | 1.17 | (0.95-1.44) | 32 | 1.03 | (0.69-1.54) |
P for trend | 0.18 | 0.79 | 0.18 | 0.79 | ||||||||
Subtype heterogeneity2 | 0.40 | 0.34 | ||||||||||
Ever a full-term birth | ||||||||||||
No | 446 | 1.00 | Reference | 115 | 1.00 | Reference | 446 | 1.00 | Reference | 115 | 1.00 | Reference |
Yes | 2994 | 0.86 | (0.77-0.95) | 843 | 0.97 | (0.80-1.19) | 2994 | 0.87 | (0.78-0.96) | 843 | 0.98 | (0.80-1.20) |
P for significance | 0.003 | 0.78 | 0.01 | 0.78 | ||||||||
Subtype heterogeneity2 | 0.92 | 0.88 | ||||||||||
Number of full-term childbirths 4 | ||||||||||||
1 child | 612 | 1.00 | Reference | 160 | 1.00 | Reference | 612 | 1.00 | Reference | 160 | 1.00 | Reference |
2 children | 1497 | 0.92 | (0.84-1.01) | 432 | 1.02 | (0.85-1.22) | 1497 | 0.92 | (0.84-1.01) | 432 | 1.01 | (0.84-1.22) |
>3 children | 840 | 0.77 | (0.69-0.85) | 244 | 0.89 | (0.72-1.09) | 840 | 0.76 | (0.68-0.85) | 244 | 0.89 | (0.73-1.10) |
P for trend | <0.001 | 0.19 | <0.001 | 0.19 | ||||||||
Subtype heterogeneity2 | 0.22 | 0.20 | ||||||||||
Age at first full-term childbirth 4 | ||||||||||||
≤19 years | 357 | 1.00 | Reference | 103 | 1.00 | Reference | 357 | 1.00 | Reference | 103 | 1.00 | Reference |
20–24 years | 1369 | 1.06 | (0.94-1.20) | 431 | 1.20 | (0.97-1.50) | 1369 | 1.07 | (0.95-1.21) | 431 | 1.20 | (0.96-1.50) |
25–29 years | 912 | 1.20 | (1.06-1.36) | 242 | 1.16 | (0.92-1.47) | 912 | 1.22 | (1.07-1.39) | 242 | 1.17 | (0.92-1.50) |
30–34 years | 275 | 1.35 | (1.15-1.59) | 61 | 1.10 | (0.80-1.52) | 275 | 1.39 | (1.18-1.64) | 61 | 1.12 | (0.81-1.56) |
≤35 years | 82 | 1.44 | (1.13-1.83) | 14 | 0.91 | (0.52-1.60) | 82 | 1.47 | (1.15-1.88) | 14 | 0.93 | (0.53-1.65) |
P for trend | <0.001 | 0.96 | <0.001 | 0.96 | ||||||||
Subtype heterogeneity2 | 0.02 | 0.03 | ||||||||||
Time between menarche and first full-term childbirth 4 | ||||||||||||
<10 years | 837 | 1.00 | Reference | 257 | 1.00 | Reference | 837 | 1.00 | Reference | 257 | 1.00 | Reference |
≥10 years | 2133 | 1.21 | (1.12-1.31) | 592 | 1.14 | (0.98-1.32) | 2133 | 1.22 | (1.12-1.33) | 592 | 1.15 | (0.99-1.34) |
P for significance | <0.001 | 0.09 | <0.001 | 0.09 | ||||||||
Subtype heterogeneity2 | 0.49 | 0.52 | ||||||||||
Age at last full-term childbirth 4 | ||||||||||||
≤24 years | 463 | 1.00 | Reference | 138 | 1.00 | Reference | 463 | 1.00 | Reference | 138 | 1.00 | Reference |
25–29 years | 1058 | 0.98 | (0.88-1.10) | 321 | 1.01 | (0.82-1.23) | 1058 | 0.98 | (0.88-1.10) | 321 | 1.01 | (0.82-1.23) |
30–34 years | 984 | 1.07 | (0.95-1.20) | 263 | 0.97 | (0.78-1.19) | 984 | 1.07 | (0.96-1.20) | 263 | 0.98 | (0.79-1.21) |
≥35 years | 490 | 1.11 | (0.97-1.26) | 130 | 1.01 | (0.79-1.29) | 490 | 1.12 | (0.98-1.28) | 130 | 1.03 | (0.80-1.33) |
P for trend | 0.03 | 0.90 | 0.02 | 0.90 | ||||||||
Subtype heterogeneity2 | 0.24 | 0.29 | ||||||||||
Time since last full-term childbirth 4 | ||||||||||||
≤20 years | 1043 | 1.00 | Reference | 300 | 1.00 | Reference | 1043 | 1.00 | Reference | 300 | 1.00 | Reference |
>20 years | 1952 | 0.87 | (0.78-0.96) | 552 | 1.00 | (0.82-1.22) | 1952 | 0.86 | (0.77-0.95) | 552 | 0.98 | (0.81-1.20) |
P for significance | 0.01 | 0.98 | 0.01 | 0.98 | ||||||||
Subtype heterogeneity2 | 0.20 | 0.24 | ||||||||||
Ever breast-fed 4 | ||||||||||||
No | 538 | 1.00 | Reference | 152 | 1.00 | Reference | 538 | 1.00 | Reference | 152 | 1.00 | Reference |
Yes | 2317 | 0.99 | (0.90-1.09) | 642 | 0.97 | (0.81-1.16) | 2317 | 0.99 | (0.89-1.09) | 642 | 0.98 | (0.81-1.17) |
P for significance | 0.82 | 0.74 | 0.76 | 0.74 | ||||||||
Subtype heterogeneity2 | 0.85 | 0.93 | ||||||||||
Total cumulative breastfeeding duration 4,5 | ||||||||||||
<1 month | 249 | 1.00 | Reference | 72 | 1.00 | Reference | 249 | 1.00 | Reference | 72 | 1.00 | Reference |
1–3 months | 602 | 1.04 | (0.89-1.20) | 155 | 0.91 | (0.69-1.21) | 602 | 1.04 | (0.89-1.20) | 155 | 0.91 | (0.69-1.21) |
4–6 months | 460 | 0.97 | (0.83-1.14) | 137 | 0.98 | (0.74-1.32) | 460 | 0.97 | (0.83-1.14) | 137 | 0.99 | (0.74-1.32) |
7–12 months | 487 | 0.97 | (0.83-1.13) | 132 | 0.91 | (0.68-1.22) | 487 | 0.97 | (0.83-1.13) | 132 | 0.91 | (0.68-1.23) |
13–17 months | 182 | 0.91 | (0.75-1.11) | 62 | 1.10 | (0.78-1.57) | 182 | 0.92 | (0.75-1.12) | 62 | 1.12 | (0.79-1.60) |
≥18 months | 293 | 1.09 | (0.91-1.31) | 77 | 1.04 | (0.73-1.46) | 293 | 1.11 | (0.92-1.33) | 77 | 1.07 | (0.75-1.51) |
P for trend | 0.99 | 0.54 | 0.90 | 0.54 | ||||||||
Subtype heterogeneity2 | 0.58 | 0.53 | ||||||||||
Ever an abortion 6 | ||||||||||||
No | 1552 | 1.00 | Reference | 435 | 1.00 | Reference | 1552 | 1.00 | Reference | 435 | 1.00 | Reference |
Yes | 1016 | 1.00 | (0.92-1.08) | 293 | 1.00 | (0.86-1.16) | 1016 | 0.99 | (0.91-1.07) | 293 | 1.00 | (0.86-1.16) |
P for significance | 0.97 | 0.98 | 0.72 | 0.98 | ||||||||
Subtype heterogeneity2 | 0.97 | 0.86 | ||||||||||
OC use at recruitment | ||||||||||||
Never OC user | 1477 | 1.00 | Reference | 379 | 1.00 | Reference | 1477 | 1.00 | Reference | 379 | 1.00 | Reference |
Past OC user | 1839 | 1.00 | (0.93-1.08) | 548 | 1.11 | (0.96-1.28) | 1839 | 0.97 | (0.90-1.05) | 548 | 1.09 | (0.94-1.26) |
Current OC user | 108 | 1.20 | (0.97-1.47) | 33 | 1.08 | (0.73-1.59) | 108 | 1.19 | (0.96-1.47) | 33 | 1.09 | (0.74-1.63) |
P for trend | 0.42 | 0.20 | 0.95 | 0.20 | ||||||||
Subtype heterogeneity7 | 0.34 | 0.30 | ||||||||||
Age started OC 8 | ||||||||||||
≤24 years | 899 | 1.00 | Reference | 292 | 1.00 | Reference | 899 | 1.00 | Reference | 292 | 1.00 | Reference |
25–29 years | 335 | 0.86 | (0.75-0.99) | 94 | 0.86 | (0.66-1.11) | 335 | 0.87 | (0.76-1.00) | 94 | 0.86 | (0.66-1.11) |
30–34 years | 303 | 0.91 | (0.78-1.07) | 90 | 0.92 | (0.69-1.23) | 303 | 0.93 | (0.79-1.08) | 90 | 0.92 | (0.69-1.22) |
≥35 years | 265 | 1.07 | (0.90-1.28) | 73 | 0.97 | (0.70-1.36) | 265 | 1.09 | (0.91-1.30) | 73 | 0.97 | (0.70-1.36) |
P for trend | 0.83 | 0.75 | 0.67 | 0.75 | ||||||||
Subtype heterogeneity2 | 0.70 | 0.61 | ||||||||||
Duration of OC use 8 | ||||||||||||
1 year or less | 396 | 1.00 | Reference | 114 | 1.00 | Reference | 396 | 1.00 | Reference | 114 | 1.00 | Reference |
2–4 years | 450 | 1.02 | (0.89-1.17) | 116 | 0.86 | (0.66-1.12) | 450 | 1.03 | (0.89-1.18) | 116 | 0.86 | (0.67-1.12) |
5–9 years | 426 | 1.06 | (0.92-1.22) | 122 | 0.97 | (0.75-1.26) | 426 | 1.06 | (0.92-1.22) | 122 | 0.97 | (0.75-1.27) |
≥10 years | 521 | 1.02 | (0.89-1.17) | 187 | 1.11 | (0.87-1.41) | 521 | 1.02 | (0.89-1.18) | 187 | 1.11 | (0.87-1.42) |
P for trend | 0.70 | 0.21 | 0.68 | 0.21 | ||||||||
Subtype heterogeneity2 | 0.36 | 0.37 |