TABLE 1.
Characteristics of the study participants by group1
| Characteristic | All | Group H-L | Group L-H | P-value2 |
| n | 96 | 48 | 48 | |
| Drop-outs, n (%) | 14 (15) | 8 (17) | 6 (13) | 0.56 |
| Ethnicity, n (%) | ||||
| White | 48 (50) | 23 (48) | 25 (52) | |
| Asian | 26 (27) | 14 (29) | 12 (25) | |
| Other | 22 (23) | 11 (23) | 11 (23) | 0.89 |
| Age at screening, y | 39.1 ± 6.4 | 40.7 ± 6.0 | 37.6 ± 6.4 | 0.02 |
| BMI, 2 | 25.9 ± 5.6 | 25.7 ± 5.1 | 26.0 ± 6.1 | 0.82 |
| Age at menarche, y | 12.5 ± 1.4 | 12.6 ± 1.4 | 12.4 ± 1.5 | 0.67 |
| Number of children | 1.5 ± 1.3 | 1.6 ± 1.1 | 1.4 ± 1.4 | 0.30 |
| Age at first live birth,3y | 28 ± 6.7 | 27.9 ± 7.3 | 28.2 ± 6.1 | 0.86 |
| Breastfeeding duration,3mo | 16.5 ± 26.2 | 15.3 ± 22.2 | 17.7 ± 30.1 | 0.66 |
| NAF volume, μL | ||||
| Baseline | 33 ± 38 | 33 ± 41 | 33 ± 34 | 0.95 |
| mo 3 | 24 ± 22 | 25 ± 18 | 24 ± 24 | 0.73 |
| mo 6 | 32 ± 36 | 37 ± 40 | 28 ± 32 | 0.27 |
| mo 7 | 24 ± 25 | 25 ± 21 | 23 ± 28 | 0.67 |
| mo 10 | 24 ± 29 | 27 ± 32 | 21 ± 24 | 0.39 |
| mo 13 | 29 ± 33 | 29 ± 36 | 29 ± 30 | 0.98 |
| Soy intake,4servings/wk | ||||
| Early life | 1.5 ± 3.4 | 0.6 ± 0.04 | 2.3 ± 1.1 | 0.02 |
| Adulthood | 3.9 ± 4.5 | 2.8 ± 3.3 | 5.0 ± 5.2 | 0.01 |
| Lifetime | 2.6 ± 3.6 | 1.7 ± 2.4 | 3.5 ± 4.3 | 0.01 |
| Urinary isoflavones, μmol/mmol creatinine | 0.564 ± 1.046 | 0.823 ± 1.281 | 0.317 ± 0.687 | 0.03 |
| Self-reported isoflavone intake, mg/d | 20.6 ± 39.4 | 15.5 ± 4.7 | 25.7 ± 13.5 | 0.21 |
1
Data are (%) or means ± SD.
2
P-values for comparison between groups by Student's t test, 2-tailed, 2-sample, unequal variance for numerical variables or χ2-test for categorical variables.
3
n = 70 for parous women: 38 in group H-L and 32 in group L-H.
4
Based on a lifetime soy questionnaire that inquired about soy intake during childhood, adolescence, and early and late adulthood; 1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts.