| Cases (n = 411) | Controls (n = 1,212) | P * |
---|---|---|---|
Demographic factors | |||
Mean age, years (SD) | 54.9 (7.6) | 54.9 (7.5) | 0.964 |
Education level, n (%) | Â | Â | 0.003 |
None | 104 (25.3) | 399 (32.9) | |
Primary | 186 (45.3) | 518 (42.7) | |
Secondary or higher | 121 (29.4) | 295 (24.3) | |
Reproductive risk factors | |||
Number of live births, n (%) | Â | Â | <0.001 |
Nulliparous | 56 (13.6) | 85 (7.0) | |
1-2 | 146 (35.5) | 369 (30.4) | |
3-4 | 131 (31.9) | 483 (39.9) | |
5 or more | 78 (19.0) | 275 (22.7) | |
Mean age at first live birth, years (SD) | 25.6 (4.9) | 25.0 (4.7) | 0.022 |
Mean age at menarche, years (SD) | 14.1 (1.7) | 14.3 (1.8) | 0.033 |
Mean age at menopause, years (SD) | 49.7 (4.4) | 49.2 (4.3) | 0.141 |
Estrogen use, n (%) | Â | Â | 0.042 |
Non-user | 372 (90.5) | 1,131 (93.3) | |
Ex-user | 8 (1.9) | 22 (1.8) | |
Current user | 31 (7.5) | 59 (4.9) | |
Other risk factors | |||
Family history of breast cancer, n (%) | Â | Â | 0.063 |
No | 400 (97.3) | 1,196 (98.7) | |
Yes | 11 (2.7) | 16 (1.3) | |
History of past biopsy, n (%) | Â | Â | 0.252 |
No | 401 (97.6) | 1,193 (98.4) | |
Yes | 10 (2.4) | 19 (1.6) | |
Mean body mass index, kg/m2 (SD) | 23.5 (3.4) | 23.2 (3.2) | 0.066 |
Marine n-3 omega fatty acids, g (SD) | 0.90 (0.4) | 0.90 (0.5) | 0.299 |
Vegetable-fruit-soy intake, n (%) | Â | Â | 0.969 |
0 | 79 (19.2) | 241 (19.9) | |
1 | 99 (24.1) | 307 (25.3) | |
2 | 130 (31.6) | 332 (27.4) | |
3 | 103 (25.1) | 332 (27.4) | |
Green tea intake in tertiles, n (%) | Â | Â | 0.418 |
None | 234 (56.9) | 713 (58.8) | |
First | 77 (18.7) | 219 (18.1) | |
Second | 43 (10.5) | 134 (11.1) | |
Third | 57 (13.9) | 146 (12.0) | |
Mean isoflavanoids, mg (SD) | 19.4 (20.4) | 19.8 (17.3) | 0.700 |
Sleep duration, hours per day (SD) | 7.0 (1.1) | 7.0 (1.1) | 0.685 |
Genetic risk score in quartiles, n (%) | Â | Â | Â |
First (32.4 - 43.6) | 80 (19.5) | 326 (26.9) | <0.001 |
Second (43.6 - 47.1) | 96 (23.4) | 310 (25.6) | Â |
Third (47.1 - 50.6) | 109 (26.5) | 296 (24.4) | Â |
Fourth (50.6 - 65.8) | 126 (30.7) | 280 (23.1) |