Table 1 Distribution of risk factors in different ages at first childbirth
From: Age at first childbirth and breast cancer survival: a prospective cohort study
Factor | Nullipara (n = 83) | < 20 years (n = 114) | 21 to ≤ 25 years (n = 252) | 26 to ≤ 30 years (n = 188) | > 30 years (n = 74) | Missing (n = 54) |
|---|---|---|---|---|---|---|
Age at baseline, year (765) Mean (SD) | 57.3 (7.7) | 55.5 (6.3) | 56.5 (7.1) | 57.2 (7.1) | 56.8 (7.9) | 57.1 (5.3) |
Socioeconomical status (720) | ||||||
Manual worker | 26.5 | 49 | 39.4 | 25.7 | 26.4 | 11.1 |
Nonmanual worker | 68.7 | 47 | 55.3 | 68.4 | 65.3 | 83.3 |
Employer-self-employed | 4.8 | 4 | 5.3 | 5.9 | 8.3 | 5.6 |
Body mass index (765) Mean (SD) | 25.6 (4.1) | 26.6 (4.1) | 25.5 (4.1) | 25.1 (3.4) | 25.6 (4.2) | 23.9 (3.2) |
Alcohol consumption (765) | ||||||
Nothing last year | 8.4 | 11.4 | 10.7 | 10.1 | 9.5 | 0 |
Something last year (not last month) | 9.6 | 13.2 | 10.7 | 6.9 | 16.2 | 1.3 |
Something last month | 81.9 | 74.6 | 78.2 | 83 | 74.3 | 94.4 |
Smoking (765) | ||||||
Never | 50.6 | 35.1 | 40.9 | 51.6 | 43.2 | 33.3 |
Current | 26.5 | 31.6 | 30.6 | 20.2 | 25.7 | 38.9 |
Ex | 22.9 | 33.3 | 28.6 | 28.2 | 31.1 | 27.8 |
Age at menarche (722) | ||||||
≤ 12 | 21.7 | 26.3 | 24 | 14.2 | 21.6 | 16.7 |
> 12 to < 15 | 47 | 53.5 | 48.4 | 59 | 56.8 | 50 |
≥ 15 | 31.3 | 20.2 | 27.6 | 26.8 | 21.6 | 33.3 |
Age at menopause (714) | ||||||
Pre/perimenopausal | 31.7 | 38.9 | 38 | 32.2 | 34.2 | 27.8 |
≤ 45 | 12.2 | 14.2 | 12.2 | 8.2 | 13.7 | 16.7 |
> 45 to < 53 | 43.9 | 34.5 | 33.9 | 46.4 | 32.9 | 44.4 |
≥ 53 | 12.2 | 12.4 | 15.9 | 13.1 | 19.2 | 11.1 |
Parity (711) | ||||||
Nullipara | 100 | 0 | 0 | 0 | 0 | 0 |
1 | 0 | 19.3 | 11.1 | 25 | 63.5 | 0 |
2 | 0 | 38.6 | 58.7 | 58 | 35.1 | – |
3 | 0 | 27.2 | 24.2 | 14.9 | 1.4 | 0 |
≥ 4 | 0 | 14.9 | 6 | 2.1 | 0 | 0 |