Table 2.
Distribution of BC risk factors related to oestrogen metabolism (Group 2) in the KBCP dataset.
| Feature names | Cases (N = 445) | Controls (N = 250) | All subjects (N = 695) | Description | p-value | |
|---|---|---|---|---|---|---|
| Oral contraceptive use | 0 | 300 (67%) | 124 (49%) | 424 (61%) | If subject has used oral contraceptives: 0: No; 1: Yes | 5e-6 |
| 1 | 145 (33%) | 126 (51%) | 271 (39%) | |||
| Oral contraceptive use duration | Mean (std) | 48.27 (51.50) | 40.86 (38.91) | 44.82 (46.22) | Duration of oral contraceptive use in months. | 0.08 |
| Menopausal status | 0 | 127 (29%) | 109 (44%) | 236 (34%) | If menopause has occurred: 0: No; 1: Yes | 8e-5 |
| 1 | 318 (71%) | 141 (56%) | 459 (66%) | |||
| Breast- feeding | 0 | 107 (24%) | 39 (16%) | 146 (21%) | Whether the subject has breast-fed: 0: No; 1: Yes | 0.01 |
| 1 | 338 (76%) | 211 (84%) | 549 (79%) | |||
| Pregnancy | 0 | 85 (19%) | 31 (12%) | 116 (17%) | Whether the subject has had a full-term pregnancy: 0: No; 1: Yes | 0.03 |
| 1 | 360 (81%) | 219 (88%) | 579 (83%) | |||
| Hormonal replacement therapy, oestrogen duration | Mean (std) | 53.94 (58.03) | 39.85 (47.86) | 48.25 (54.59) | Duration of oestrogen use in months. | 0.6 |
| Menstrual cycle length | Mean (std) | 26.94 (2.27) | 27.26 (2.65) | 27.06 (2.42) | Length of menstrual cycle in days. | 0.09 |
| First pregnancy length | Mean (std) | 39.20 (3.37) | 39.18 (3.88) | 39.19 (3.58) | Length of 1st pregnancy in weeks. | 0.12 |
| Second pregnancy length | Mean (std) | 39.66 (1.95) | 38.99 (4.64) | 39.39 (3.31) | Length of 2nd pregnancy in weeks. | 0.03 |
| Third pregnancy length | Mean (std) | 38.97 (3.93) | 38.64 (5.70) | 38.85 (4.66) | Length of 3rd pregnancy in weeks. | 0.12 |
| Body mass index (BMI) | Mean (std) | 26.49 (4.60) | 26.04 (4.29) | 26.33 (4.50) | Body mass index. | 0.2 |
The P-values denote the differences in the Group 2 features between the BC cases and controls using the chi-squared test for categorical variables and the t-test for continuous variables. The difference is statistically significant when the p-value < 0.05 (highlighted p-values). P-values were not adjusted for multiple testing. std: standard deviation.