Skip to main content

Table 2 Characteristics of the study population according to 10-year breast cancer risk estimated by the Tyrer–Cuzick prediction model

From: Background risk of breast cancer and the association between physical activity and mammographic density

  Breast cancer risk
Characteristic <3.0% 3.0 to 4.9% ≥5.0%
Number of participants (%) 19,633 (50.5) 13,785 (35.4) 5,495 (14.1)
Age at mammography screening (years), mean (SD) 52.8 (10.4) 57.9 (8.5) 58.8 (7.8)
Body mass index (kg/m2), mean (SD) 25.1 (4.2) 25.7 (4.2) 25.8 (4.1)
Age at menarche (years), mean (SD) 13.2 (1.5) 13.0 (1.4) 12.9 (1.4)
Nulliparous (%) 8.4 16.0 16.5
Age at first birth (years), mean (SD)a 26.0 (5.0) 28.2 (5.0) 28.4 (5.2)
Number of childbirths, mean (SD)a 2.3 (0.8) 2.1 (0.8) 2.1 (0.8)
Family history of breast cancer (%) 1.2 9.9 67.2
Education level (%)    
 Secondary school 14.1 13.6 12.6
 High school 33.9 27.5 26.7
 University or higher 49.0 55.5 57.5
 Other 2.7 3.2 3.1
OC use, ever (%) 80.9 79.9 79.8
Premenopausal (%) 56.7 30.8 27.9
Age at menopause (years), mean (SD)b 49.5 (5.5) 50.2 (5.2) 50.3
HRT use (%)b    
 Never 63.1 61.4 62.2
 Past 22.4 22.2 22.8
 Current 3.8 6.0 5.9
Smoking status (%)    
 Never 49.9 46.2 44.3
 Past 36.9 42.7 43.7
 Current 12.9 11.0 11.9
Alcohol consumption (grams/day)    
 None (%) 19.3 16.4 16.3
 0.1 to 9.9 (%) 61.6 61.3 59.5
 10.0 to 29.9 (%) 14.7 17.5 18.8
  ≥ 30.0 (%) 2.1 3.3 3.5
  1. HRT, hormone replacement therapy; OC, oral contraceptives; SD, standard deviation. aAmong parous women only. bAmong postmenopausal women only.
\