Table 1.

Select characteristics among participants and nonparticipants in the CWLS

Characteristic at diagnosisCWLS participants (n = 5,791)CWLS nonparticipants (n = 8,709)
Age at diagnosis, mean y (SD)58.4 (10.0)59.2 (11.0)
Breast cancer stage at diagnosis, %
    Local64.162.5
    Regional24.726.9
    Distant0.61.4
    Unknown10.69.2
Age at menarche, mean y (SD)12.7 (1.5)12.8 (1.6)
Age at first live birth, mean y (SD)24.4 (4.4)24.3 (4.5)
Parity, mean (SD)2.7 (1.8)2.6 (1.8)
Postmenopausal, %71.972.0
Postmenopausal hormone use, %*38.933.2
Education = 12 y, %91.283.1
BMI, %
    Underweight1.41.9
    Normal weight50.346.5
    Overweight30.930.6
    Obese16.418.7
Smoking history, %
    Never47.548.4
    Former34.828.9
    Current17.221.4
Alcoholic drinks per wk, mean (SD)0.5 (0.8)0.4 (0.9)
Mortality, %
    All-cause deaths15.225.2
    Breast cancer deaths6.38.9
  • * Among postmenopausal women.

  • BMI categorized as underweight (<18.5 kg/m2), normal (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), or obese (≥30 kg/m2).