Table 3.
Associations between risk factors and breast cancer subtypes by menopausal status.a
| Risk factorsb | Premenopausal |
Phd | Postmenopausal |
Phd | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Control |
Luminal |
HER2-enriched |
Triple-negative |
Control |
Luminal |
HER2-enriched |
Triple-negative |
|||||||||
| n = 831 |
n = 555 |
n = 30 |
n = 154 |
n = 585 |
n = 343 |
n = 25 |
n = 149 |
|||||||||
| n (%) | n (%) | OR (95% CI) | n (%) | OR (95% CI) | n (%) | OR (95% CI) | n (%) | n (%) | OR (95% CI) | n (%) | OR (95% CI) | n (%) | OR (95% CI) | |||
| Age, years | ||||||||||||||||
| <40 | 313 (37.7) | 221 (39.8) | 1.00 | 8 (26.7) | 1.00 | 48 (31.2) | 1.00 | – | ||||||||
| 40–59 | 518 (62.3) | 334 (60.2) | 0.85 (0.67–1.07) | 22 (73.3) | 1.43 (0.62–3.29) | 106 (68.8) | 1.25 (0.84–1.84) | 0.11 | 378 (64.6) | 208 (60.6) | 1.00 | 19 (76.0) | 1.00 | 100 (67.1) | 1.00 | |
| ≥60 | – | 207 (35.4) | 135 (39.4) | 0.80 (0.58–1.09) | 6 (24.0) | 0.31 (0.11–0.83) | 49 (32.9) | 0.52 (0.33–0.81) | 0.22 | |||||||
| BMI, kg/m2 | ||||||||||||||||
| <25 | 765 (92.1) | 478 (86.1) | 1.00 | 25 (83.3) | 1.00 | 126 (81.8) | 1.00 | 467 (79.8) | 240 (70.0) | 1.00 | 23 (92.0) | 1.00 | 106 (71.1) | 1.00 | ||
| ≥25 | 66 (7.9) | 77 (13.9) | 1.88 (1.31–2.69) | 5 (16.7) | 2.25 (0.82–6.17) | 28 (18.2) | 2.51 (1.53–4.12) | 0.55 | 118 (20.2) | 103 (30.0) | 1.48 (1.08–2.04) | 2 (8.0) | 0.31 (0.07–1.35) | 43 (28.9) | 1.24 (0.80–1.92) | 0.11 |
| Menarche age, years | ||||||||||||||||
| ≥14 | 507 (61.0) | 318 (57.3) | 1.00 | 20 (66.7) | 1.00 | 99 (64.3) | 1.00 | 418 (71.5) | 232 (67.6) | 1.00 | 24 (96.0) | 1.00 | 107 (71.8) | 1.00 | ||
| <14 | 324 (39.0) | 237 (42.7) | 1.17 (0.93–1.47) | 10 (33.3) | 0.83 (0.38–1.83) | 55 (35.7) | 0.98 (0.67–1.43) | 0.29 | 167 (28.5) | 111 (32.4) | 1.25 (0.92–1.69) | 1 (4.0) | 0.14 (0.02–1.03) | 42 (28.2) | 1.20 (0.79–1.83) | 0.05 |
| Age at first live birth, yearsc | ||||||||||||||||
| <25 | 391 (49.1) | 238 (44.4) | 1.00 | 12 (40.0) | 1.00 | 70 (47.3) | 1.00 | 243 (41.9) | 132 (39.5) | 1.00 | 8 (32.0) | 1.00 | 64 (45.7) | 1.00 | ||
| ≥25 | 406 (50.9) | 298 (55.6) | 1.39 (1.10–1.76) | 18 (60.0) | 1.72 (0.79–3.74) | 78 (52.7) | 1.43 (0.98–2.09) | 0.74 | 337 (58.1) | 202 (60.5) | 1.41 (1.04–1.90) | 17 (68.0) | 2.45 (0.97–6.18) | 76 (54.3) | 1.21 (0.81–1.81) | 0.40 |
| Breastfeedingc | ||||||||||||||||
| Yes | 748 (93.9) | 507 (94.6) | 1.00 | 27 (90.0) | 1.00 | 140 (94.6) | 1.00 | 534 (92.1) | 314 (94.0) | 1.00 | 23 (92.0) | 1.00 | 127 (90.7) | 1.00 | ||
| No | 49 (6.1) | 29 (5.4) | 0.98 (0.60–1.59) | 3 (10.0) | 1.87 (0.54–6.47) | 8 (5.4) | 1.00 (0.46–2.20) | 0.60 | 46 (7.9) | 20 (6.0) | 0.83 (0.48–1.46) | 2 (8.0) | 1.40 (0.31–6.40) | 13 (9.3) | 1.44 (0.74–2.80) | 0.54 |
| Age at post-menopause, years | ||||||||||||||||
| <55 | – | 570 (97.4) | 316 (92.1) | 1.00 | 22 (88.0) | 1.00 | 140 (94.0) | 1.00 | ||||||||
| ≥55 | – | 15 (2.6) | 27 (7.9) | 3.11 (1.61–6.02) | 3 (12.0) | 5.56 (1.41–21.93) | 9 (6.0) | 2.65 (1.12–6.33) | 0.63 | |||||||
BMI, body mass index; CI, confidence interval; OR, odds ratio.
a
Odds ratios adjusted for the other factors in this table and family history of breast cancer.
b
Considering the limited sample sizes in tumor subgroups, all the continuous variables were categorized into two levels, including BMI, age at menarche, and age at first live birth.
c
Among parous women.
d
P-value of heterogeneity of exposure-disease odds ratios among luminal, HER2-enriched, and triple-negative subtypes.