Table 1.
Selected characteristics of participants across quartiles of enterolactone levels among controls in the nested case-control study of breast cancer
| Enterolactone (nmol/L) |
||||
|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | |
| N | 209 | 197 | 196 | 200 |
| Median (10–90 percentile) | ||||
| Enterolactone, nmol/L | 1.1 (0–4.0) | 8.0 (5.0–10.9) | 16.0 (12.0–20.0) | 34.0 (23.0–83.5) |
| Enterolactone (premenopausal), nmol/L | 1.5 (0–4.0) | 7.7 (5.0–10.0) | 16.0 (12.0–20.0) | 34.0 (23.3–85.0) |
| Enterolactone (postmenopausal), nmol/L | 1.0 (0–4.0) | 8.0 (6.0–11.0) | 15.5 (12.0–19.0) | 40.0 (24.9–66.0) |
| Mean (SD) | ||||
| Age a, y | 45.2 (4.4) | 44.8 (4.2) | 44.2 (4.8) | 45.5 (4.2) |
| BMI, kg/m2 | 27.7 (6.4) | 26.0 (5.5) | 25.1 (5.2) | 24.5 (4.3) |
| BMI at age 18, kg/m2 | 21.3 (3.4) | 21.0 (2.9) | 21.0 (3.0) | 20.9 (2.5) |
| Weight change since age 18, lb | 38.7 (33.9) | 29.8 (29.2) | 23.1 (25.8) | 21.6 (25.3) |
| Duration of OC use among ever OC users, y | 3.8 (3.6) | 4.4 (4.2) | 3.9 (4.0) | 3.4 (3.4) |
| Parity among parous women | 2.9 (1.3) | 3.0 (1.3) | 3.0 (1.3) | 2.9 (1.2) |
| Alcohol intake, g/d | 3.6 (7.5) | 4.2 (8.3) | 4.9 (8.4) | 5.4 (8.3) |
| Physical activity, MET- hr/week | 15.2 (19.1) | 21.1 (35.4) | 19.0 (22.2) | 19.0 (18.8) |
| Age at menarche, y | 12.5 (1.6) | 12.6 (1.4) | 12.5 (1.3) | 12.4 (1.4) |
| Age at first birth, y | 25.6 (4.7) | 25.8 (4.4) | 26.4 (4.5) | 27.3 (4.8) |
| Luteal day of blood draw ab | 7.9 (3.6) | 7.1 (2.1) | 7.5 (2.8) | 7.5 (2.6) |
| Total calorie intake, kcal/d | 1796 (564) | 1813 (534) | 1870 (580) | 1805 (510) |
| Vegetable intake, cup/week | 25.4 (14.4) | 26.1 (14.5) | 25.0 (8.7) | 27.8 (10.2) |
| Whole grains intake, cup/week | 8.7 (4.2) | 8.4 (4.2) | 9.3 (3.9) | 10.4 (5.4) |
| Fiber, g/d | 5.2 (2.1) | 5.4 (2.2) | 5.6 (2.2) | 6.1 (2.5) |
| Caffeine, mg/d | 205 (198) | 207 (189) | 240 (195) | 241 (193) |
| Tofu, g/d | 5.7 (22.3) | 8.5 (31.2) | 11.3 (34.0) | 14.2 (31.2) |
| Estradiol (follicular), pg/mL | 52.5 (44.3) | 60.4 (43.9) | 56.4 (37.1) | 54.7 (36.6) |
| Estradiol (luteal), pg/mL | 138 (107) | 150 (85) | 147 (77) | 152 (74) |
| Percentage | ||||
| Caucasian a | 96.7 | 99.5 | 98.5 | 98.5 |
| Family history of breast cancer | 8.6 | 10.7 | 11.2 | 10.0 |
| History of benign breast disease | 14.8 | 19.3 | 14.3 | 22.5 |
| Antibiotics use in last month | 17.7 | 11.2 | 7.7 | 8.0 |
| Current smokers | 12.4 | 6.1 | 4.1 | 4.0 |
| Post-menopausal at blood collection a | 18.2 | 10.7 | 12.2 | 14.5 |
| Post-menopausal hormone use at blood collection among post-menopausal women a | 83.6 | 87.8 | 87.0 | 83.3 |
a
Matching factors
b
Date of next menstrual cycle minus date of blood collection