Table 1.
Characteristics of postmenopausal women not using hormone therapy whose plasma hormone levels were measured in the Nurses’ Health Study (n=1976).
| Characteristic | All participants (n=1976) |
|---|---|
| Age at blood draw, y (Mean, SD) | 61.4 (4.7) |
| Age at menarche, y (Mean, SD) | 12.7 (1.4) |
| Irregular cycles (n, %) | 252 (13.6%) |
| Parous (n, %) | 1892 (95.8%) |
| Parity (Mean, SD)* | 3.5 (1.7) |
| Ever breastfed (n, %) | 1275 (64.5%) |
| Duration of breastfeeding, y (Mean, SD)† | 0.7 (0.8) |
| Ever OC use (n, %) | 633 (32.2%) |
| Duration of OC use, y (Mean, SD)‡ | 4.4 (4.4) |
| Age at menopause, y (Mean, SD) | 50.4 (3.2) |
| Years since menopause, y (Mean, SD) | 11.0 (5.2) |
| Hysterectomy (n, %) | 346 (17.5%) |
| Unilateral oophorectomy (n, %) | 127 (6.4%) |
| Ovulatory years (Mean, SD) | 32.4 (5.2) |
| BMI at blood draw, kg/m2 (Mean, SD) | 25.8 (4.7) |
| Smoking status (n, %) | |
| Never | 885 (44.8%) |
| Former | 819 (41.5%) |
| Current | 272 (13.8%) |
| Alcohol (grams/day) | |
| No regular use | 787 (41.7%) |
| ≤20 | 964 (51.1%) |
| >20 | 135 (7.2%) |
| Plasma hormone levels (median, 10th - 90th percentile, n) | |
| Estradiol (pg/mL) | 5.0 (2.7–10.6), 1624 |
| Estrone (pg/mL) | 22.9 (12.8–41.8), 1536 |
| Estrone sulfate (pg/mL) | 230.4 (98.3–544.9), 1182 |
| Testosterone (ng/dL) | 19.8 (10.4–37.5), 1869 |
| DHEAS (ug/dL) | 61.2 (22.9–135.1), 1374 |
| Prolactin (ng/mL) | 8.8 (5.3–15.6), 1192 |
| SHBG (nmol/L) | 58.5 (28.1–103.1), 1779 |
*
Among parous women
†
Among women who ever breastfed
‡
Among women who ever used OCs