From: The Million Women Study: design and characteristics of the study population
 | Sufficient information and/or permission for follow-up | |
---|---|---|
Characteristic | Yes (n = 113 104) | No (n = 8025) |
Average age (years) | 56.1 | 56.2 |
Average age at leaving school (years) | 15 | 15 |
Average height (m) | 1.62 | 1.62 |
Average weight (kg) | 68.5 | 67.5 |
Current smoker (%) | 18 | 18 |
Drink alcohol (%) | 78 | 72 |
Exercise at least once a week (%) | 43 | 42 |
Parous (%) | 89 | 84 |
Average number of children | 2.4 | 2.4 |
Average age at first birth (years) | 24.0 | 24.3 |
Previous breast cancer screen (%) | 79 | 76 |
Previous diagnosis of breast cancer (%) | 1.4 | 0.9 |
Mother or sister with a history of breast | 9 | 8 |
cancer (%) | Â | Â |
Previous use of oral contraceptives (%) | 54 | 45 |
Current use of HRT (%) | 33 | 25 |
Past use of HRT (%) | 15 | 14 |