Baseline characteristics of women in the derivation and validation cohorts
| Derivation cohort (n = 1 240 864) | Validation cohort (n = 667 603) | |
|---|---|---|
| Mean age (SD) | 50.3 (17.5) | 50.1 (17.4) |
| BMI recorded, n (%) | 924 268 (74.5) | 480 001 (71.9) |
| Mean BMI (SD) | 25.8 (4.9) | 25.8 (4.9) |
| Mean deprivation score, (SD) | −0.4 (3.3) | −0.2 (3.5) |
| Smoking status, n (%) | ||
| Non-smoker | 640 775 (51.6) | 342 137 (51.2) |
| Ex-smoker | 215 060 (17.3) | 105 411 (15.8) |
| Current: amount not recorded | 26 749 (2.2) | 14 151 (2.1) |
| Light (<10/day) | 68 059 (5.5) | 35 608 (5.3) |
| Moderate (10–19/day) | 92 337 (7.4) | 50 146 (7.5) |
| Heavy (≥20/day) | 50 831 (4.1) | 27 711 (4.2) |
| Smoking not recorded | 147 053 (11.9) | 92 439 (13.9) |
| Alcohol status, n (%) | ||
| None | 325 730 (26.3) | 169 033 (25.3) |
| Trivial <1 unit/day | 402 453 (32.4) | 203 775 (30.5) |
| Light 1–2 units/day | 192 736 (15.5) | 100 051 (15.0) |
| Moderate or heavy ≥3 units/day | 25 003 (2.0) | 13 039 (2.0) |
| Alcohol not recorded | 294 942 (23.8) | 181 705 (27.2) |
| Medical and family history, n (%) | ||
| Prior cancer | 34 324 (2.8) | 17 863 (2.7) |
| Family history of breast cancer | 45 621 (3.7) | 22 043 (3.3) |
| Family history of gastrointestinal cancer | 18 759 (1.5) | 8780 (1.3) |
| Family history of ovarian cancer | 2417 (0.2) | 1192 (0.2) |
| Benign breast disease | 41 728 (3.4) | 20 687 (3.1) |
| Chronic pancreatitis | 1042 (0.1) | 539 (0.1) |
| Chronic obstructive pulmonary disease | 21 516 (1.7) | 11 358 (1.7) |
| Type 1 diabetes | 3523 (0.3) | 1921 (0.3) |
| Type 2 diabetes | 37 827 (3.0) | 20 372 (3.1) |
| Endometriosis | 13 563 (1.1) | 7153 (1.1) |
| Endometrial hyperplasia or polyp | 3235 (0.3) | 1621 (0.2) |
| Fibroids | 18 796 (1.5) | 10 291 (1.5) |
| Polycystic ovarian disease | 10 756 (0.9) | 5993 (0.9) |
| Rheumatoid arthritis | 13 825 (1.1) | 7153 (1.1) |
| Systemic lupus erythematosus | 1443 (0.1) | 687 (0.1) |
| HIV or AIDS | 4186 (0.3) | 2907 (0.4) |
| Oral contraceptive | 120 840 (9.7) | 61 830 (9.3) |
| Hormone replacement therapy | 26 275 (2.1) | 13 402 (2.0) |
| Anaemia | 38 804 (3.1) | 19 921 (3.0) |
BMI = body mass index. SD = standard deviation.