Table 1 Distribution of established and potential risk factors for breast cancer in women with breast cancer and the rest of cohort
Factor | CIS n = 21 | Invasive n = 149 | Rest of cohort* n = 2015 | All n = 2185 |
|---|---|---|---|---|
(column percent; mean (SD) in italics) | ||||
Age at baseline (years) | 48.1(6.7) | 49.9(6.5) | 50.5(6.4) | 50.4(6.4) |
Age <50 | 57.1 | 43.6 | 39.2 | 39.7 |
Age >50 | 42.9 | 56.4 | 60.8 | 60.3 |
BMI (kg/m2) | 25.1(5.8) | 24.7(4.4) | 24.2(4.1) | 24.3(4.1) |
BMI <20 | 9.5 | 7.4 | 10.3 | 10.1 |
BMI ≥20 < 25 | 52.4 | 51.7 | 55.0 | 54.7 |
BMI ≥25 < 30 | 23.8 | 29.5 | 25.2 | 25.5 |
BMI ≥30 | 14.3 | 11.4 | 9.5 | 9.7 |
Age at menarche | ||||
<12 years | 9.5 | 14.1 | 12.6 | 12.6 |
>12 years | 90.5 | 84.6 | 86.7 | 86.6 |
Missing | - | 1.3 | 0.7 | 0.7 |
Oral contraceptives | ||||
Yes | 9.5 | 6.0 | 7.7 | 7.6 |
No | 90.5 | 93.3 | 91.9 | 92.0 |
Missing | - | 0.7 | 0.3 | 0.4 |
Postmenopausal | ||||
Yes | 47.6 | 56.4 | 61.0 | 60.5 |
No | 52.6 | 43.6 | 39.0 | 39.5 |
Children | ||||
Yes | 76.2 | 77.9 | 83.1 | 82.6 |
No | 23.8 | 21.5 | 16.7 | 17.1 |
Missing | - | 0.7 | 0.2 | 0.3 |
HRT in postmenopausal | ||||
Yes | 10 | 11.9 | 15.7 | 15.4 |
No | 90 | 88.1 | 84.2 | 84.5 |
Missing | - | - | 0.1 | 0.1 |
Smoking status | ||||
Never | 42.9 | 51.7 | 46.3 | 46.6 |
Ex | 23.8 | 20.1 | 19.0 | 19.1 |
Current | 33.3 | 27.5 | 34.5 | 34.0 |
Missing | - | 0.7 | 0.3 | 0.3 |
Married | ||||
Yes | 42.9 | 60.4 | 52.4 | 52.9 |
No | 47.6 | 31.5 | 42.0 | 41.3 |
Missing | 9.5 | 8.1 | 5.6 | 5.8 |
Alcohol consumption | ||||
None | 9.5 | 20.8 | 14.7 | 15.1 |
Less than every week | 57.1 | 53.7 | 60.2 | 59.7 |
Every week | 33.3 | 24.8 | 24.6 | 24.7 |
Missing | - | 0.7 | 0.5 | 0.5 |
Education | ||||
≤12 years | 76.2 | 79.1 | 81.6 | 81.4 |
>12 years | 23.8 | 16.9 | 14.4 | 14.6 |
Missing | - | 4.0 | 4.0 | 4.0 |