Table 2:
Baseline characteristics of all premenopausal women randomized to placebo or isoflavones
| Placebo | Isoflavones | |||||
|---|---|---|---|---|---|---|
| Characteristics* | n | Mean (SD) | n | Mean (SD) | ||
| Age at consent (year) | 98 | 37.35 | (3.45) | 99 | 37.58 | (2.95) |
| Race/ethnicity (%) | 98 | 99 | ||||
| Hispanic | 39 | 39.80 | 51 | 51.52 | ||
| African American | 12 | 12.24 | 14 | 14.14 | ||
| White | 47 | 47.96 | 34 | 34.34 | ||
| BMI (kg/m2) | 98 | 29.17 | (6.33) | 99 | 28.45 | (6.05) |
| Waist-to-hip ratio | 97 | 0.83 | (0.06) | 99 | 0.83 | (0.06) |
| Urinary level | ||||||
| Riboflavin (μg/mL) | 91 | 0.66 | (1.00) | 93 | 0.82 | (1.72) |
| Daidzein (mg/h) | 90 | 0.06 | (0.03) | 89 | 0.07 | (0.04) |
| Genistein (mg/h) | 90 | 0.08 | (0.05) | 89 | 0.08 | (0.04) |
| Serum level | ||||||
| Cholesterol (mg/dL) | 98 | 182.00 | (30.40) | 99 | 182.90 | (27.78) |
| HDL (mg/dL) | 98 | 53.05 | (12.35) | 99 | 55.87 | (10.47) |
| LDL (mg/dL) | 98 | 109.00 | (26.79) | 99 | 108.50 | (24.73) |
| Albumin (g/dL) | 98 | 4.28 | (0.34) | 99 | 4.28 | (0.26) |
| Calcium (mg/dL) | 98 | 9.01 | (0.35) | 99 | 9.05 | (0.28) |
| Magnetic resonance image† | ||||||
| Total breast (cc) | 97 | 829.20 | (448.50) | 95 | 807.60 | (424.30) |
| Fibroglandular breast tissue (FGBT) (cc) | 97 | 164.80 | (90.03) | 95 | 166.50 | (85.42) |
| Fatty breast tissue (FBT) (cc) | 97 | 664.40 | (427.40) | 95 | 641.00 | (399.30) |
| FGBT%, % of total breast | 97 | 23.86 | (13.99) | 95 | 24.76 | (14.54) |
| Mammographic density, % of total breast§ | 98 | 26.73 | (10.83) | 96 | 27.77 | (11.62) |
| Study visits | 98 | 8.60 | (3.00) | 99 | 8.70 | (3.10) |
*
Variables were average of 4 baseline screening visits except for race/ethnicity. Study visits were mean number of baseline and completed follow-up visit. All P values > 0.05 for two group comparisons.
†
One placebo and 4 isoflavone subjects had missing or unsatisfactory baseline MRI.
§
A signal intensity from a pixel signal intensity histogram of each digital mammogram was selected to best segment FGBT from FBT, and pixel counts in FGBT was divided by pixel counts in total breast. Baseline mammograms were missing for 3 isoflavone subjects.