Table 1 Baseline characteristics of women by residence and dataset in China Kadoorie Biobank (CKB) and Shanghai Women’s Health Study (SWHS)
| Â | CKB | SWHS | |||
|---|---|---|---|---|---|
Rural | Urban | Urban | |||
Derivation | Validation | Derivation | Validation | ||
No. of participants, n | 111,346 | 55,612 | 89,204 | 44,662 | 73,203 |
Cases, n | 529 | 267 | 1007 | 484 | 1409 |
Age in years, mean (SD) and % | |||||
 Continuous, years | 50.5 (10.2) | 50.5 (10.2) | 52.6 (10.7) | 52.6 (10.7) | 52.5 (9.1) |
 30- | 2.4 | 2.4 | 1.7 | 1.5 | -- |
 35- | 15.8 | 15.7 | 11.6 | 11.4 | -- |
 40- | 18.3 | 18.4 | 15.9 | 16.1 | 28.3 |
 45- | 13.2 | 13.2 | 14.2 | 14.6 | 20.8 |
 50- | 17.6 | 17.5 | 17.1 | 17.4 | 14.1 |
 55- | 13.6 | 13.6 | 13.5 | 13.4 | 11.1 |
 60- | 8.9 | 9.0 | 9.7 | 9.3 | 12.8 |
 65- | 6.1 | 5.9 | 9.1 | 9.2 | 13.3 |
 70- | 3.7 | 3.8 | 6.4 | 6.4 | 0.6 |
 75- | 0.4 | 0.4 | 0.8 | 0.8 | -- |
Highest education, % | |||||
 No formal school | 31.9 | 31.5 | 17.3 | 17.1 | 10.6 |
 Primary school | 40.3 | 40.5 | 20.4 | 20.0 | 10.8 |
 Middle school | 21.6 | 21.6 | 29.9 | 30.4 | 37.2 |
 High school | 5.6 | 5.8 | 23.2 | 23.3 | 28.0 |
 College/university | 0.6 | 0.6 | 9.2 | 9.1 | 13.5 |
Ever smoker, % | 5.6 | 5.5 | 4.4 | 4.6 | 2.8 |
Ever weekly drinker, % | 3.2 | 3.2 | 2.6 | 2.6 | 2.3 |
BMI, mean (SD) and % | |||||
 Continuous, kg/m2 | 23.5 (3.4) | 23.5 (3.4) | 24.2 (3.5) | 24.3 (3.5) | 24.0 (3.4) |
 < 18.5 | 5.2 | 5.1 | 3.2 | 3.0 | 3.4 |
 18.5–23.9 | 53.8 | 53.4 | 46.6 | 46.5 | 49.9 |
 24.0–27.9 | 31.2 | 31.6 | 36.1 | 36.3 | 34.6 |
 ≥ 28 | 9.9 | 9.9 | 14.0 | 14.2 | 12.2 |
Height, mean (SD) and % | |||||
 Continuous, cm | 153.2 (5.9) | 153.2 (5.9) | 155.3 (5.9) | 155.3 (5.9) | 157.5 (5.5) |
 < 150.2 | 29.4 | 29.4 | 19.3 | 19.1 | 10.3 |
 150.2–154.1 | 26.3 | 26.1 | 23.6 | 23.5 | 17.6 |
 154.2–158.1 | 24.1 | 24.3 | 26.1 | 26.1 | 27.9 |
 ≥ 158.2 | 20.2 | 20.1 | 31.0 | 31.3 | 44.2 |
No. of affected first-degree relatives, % | |||||
 0 | 85.2 | 85.5 | 80.6 | 80.4 | 74.7 |
 1 | 13.0 | 12.7 | 16.8 | 16.9 | 21.5 |
 ≥2 | 1.8 | 1.9 | 2.6 | 2.7 | 3.8 |
Postmenopausal, % | 50.2 | 50.2 | 55.0 | 55.3 | 49.2 |
No. of live birth, mean (SD) and % | |||||
 Continuous | 2.5 (1.4) | 2.5 (1.4) | 1.9 (1.2) | 1.9 (1.2) | 1.8 (1.2) |
 Nulliparous | 0.8 | 0.9 | 1.9 | 1.9 | 3.3 |
 1 | 21.1 | 21.3 | 50.8 | 51.2 | 54.9 |
 2 | 38.6 | 38.2 | 23.6 | 23.2 | 21.1 |
 ≥ 3 | 39.4 | 39.6 | 23.7 | 23.7 | 20.8 |
Age at menarche, mean (SD) and % | |||||
 Continuous, years | 15.6 (1.9) | 15.5 (1.9) | 15.3 (2.0) | 15.3 (2.0) | 14.9 (1.7) |
 < 12 | 4.7 | 4.7 | 6.4 | 6.4 | 6.3 |
 13–14 | 26.3 | 26.4 | 30.3 | 30.3 | 36.5 |
 15–16 | 38.3 | 38.4 | 36.1 | 36.1 | 39.5 |
 ≥ 17 | 30.6 | 30.5 | 27.2 | 27.3 | 17.8 |
Total months of breastfeeding, mean (SD) and % | |||||
 Continuous, months | 42.4 (32.2) | 42.5 (32.4) | 24.0 (22.8) | 23.9 (22.5) | 15.5 (18.3) |
 0 | 2.2 | 2.4 | 6.3 | 6.3 | 20.2 |
 1–23.9 | 36.5 | 36.5 | 64.1 | 64.1 | 56.6 |
 24–35.9 | 17.4 | 17.2 | 12.1 | 12.1 | 9.9 |
 36–47.9 | 14.2 | 14.0 | 7.0 | 7.1 | 5.9 |
 ≥ 48 | 29.6 | 29.9 | 10.4 | 10.3 | 7.4 |
Pill use, % | |||||
 Never | 91.2 | 91.4 | 88.7 | 88.8 | 78.6 |
 Ever | 8.8 | 8.6 | 11.3 | 11.2 | 20.4 |