Table 1 Participant characteristics (at the DISC06 follow-up visit)
Descriptive characteristic | n | Mean (SD) or % |
|---|---|---|
Age (y) | 182 | 27.2 (1.0) |
Percent dense breast volume (%) | 182 | 27.6 (20.5) |
Absolute dense breast volume (cm3) | 182 | 104.2 (70.6) |
Absolute non-dense breast volume (cm3) | 182 | 413.5 (364.3) |
Body mass index (BMI) (kg/m2) | 182 | 24.4 (5.4) |
Height (cm) | 182 | 165.3 (6.4) |
BMI Z-score at 8–10 years old | 182 | 0.23 (0.90) |
Age at menarche (y) | 182 | 12.9 (1.3) |
Duration of hormonal contraceptive use (y)a | 171 | 5.6 (3.5) |
Race | Â | Â |
    White | 164 | 90.1 % |
    Non-white | 18 | 9.9 % |
Education | Â | Â |
    High school, vocational, or technical school | 18 | 9.9 % |
    Some college | 44 | 24.2 % |
    College/Bachelor’s | 95 | 52.2 % |
    Graduate school | 25 | 13.7 % |
Number of live births | Â | Â |
    0 | 129 | 73.1 % |
    1 | 30 | 16.5 % |
    2+ | 23 | 12.6 % |
Ever breast fed (among parous) | Â | Â |
    Yes | 40 | 75.4 % |
    No | 13 | 24.5 % |
Hormonal contraceptive use | Â | Â |
    Never | 11 | 6.0 % |
    Former | 66 | 36.3 % |
    Current | 105 | 57.7 % |
Family history of breast cancer | Â | Â |
    Yes | 7 | 3.9 % |
    No | 171 | 96.1 % |
Alcohol consumption | Â | Â |
    Never/former | 16 | 8.8 % |
    Current, <3 drinks per week | 71 | 39.0 % |
    Current, 3–<6 drinks per week | 33 | 18.1 % |
    Current, 6– <10 drinks per week | 40 | 22.0 % |
    Current, 10+ drinks per week | 22 | 12.1 % |
Smoking history | Â | Â |
    Never | 100 | 55.0 % |
    Former | 38 | 20.9 % |
    Current | 44 | 24.2 % |
Treatment assignment | Â | Â |
    Intervention | 87 | 47.8 % |
    Usual care | 95 | 52.2 % |