Table 1.
Characteristics of premenopausal women in the Nurses’ Health Study II (n = 2,745).
| Mean (SD) or % | |
|---|---|
| Age at blood draw (yr) | 42.7 (4.0) |
| BMI1 at age 18 (kg/m2) | 21.1 (3.1) |
| BMI at blood draw (kg/m2) | 25.6 (5.8) |
| Parous, % | 80.9 |
| Parity (among parous women) | 2.3 (0.9) |
| Past oral contraceptive use, % | 84.6 |
| Ever smoker, % | 30.6 |
| Alcohol intake (grams/day) | 3.6 (7.0) |
| Physical activity2 (METs/week) | 19.1 (22.8) |
| Time between return of 1993 questionnaire and blood draw (months) | 51.4 (9.5) |
| Age at menarche (yr), % | |
| ≤11 | 22.2 |
| 12 | 29.7 |
| 13 | 28.6 |
| ≥14 | 19.5 |
| Menstrual cycle length when age 18–22 (days), % | |
| ≤25 | 10.3 |
| 26–31 | 65.3 |
| 32–39 | 16.6 |
| ≥40 or irregular | 7.9 |
| Menstrual cycle regularity when age 18–22, % | |
| Very regular | 42.3 |
| Regular | 34.8 |
| Irregular | 22.9 |
| Menstrual cycle length in 1993 (days), % | |
| ≤25 | 17.0 |
| 26–31 | 70.7 |
| ≥32 | 12.3 |
| Menstrual cycle regularity in 1993, % | |
| Very regular | 68.6 |
| Regular | 25.0 |
| Irregular | 6.5 |
|
| |
| Median (10th – 90th percentile) | |
|
| |
| Estradiol, pg/mL | |
| Follicular phase | 46.5 (22.2 −101.1) |
| Luteal phase | 133 (72 – 236) |
| Free Estradiol, pg/mL | |
| Follicular phase | 0.6 (0.3 – 1.2) |
| Luteal phase | 1.7 (0.9 – 2.8) |
| Estrone, pg/mL | |
| Follicular phase | 40.6 (25.0 – 67.6) |
| Luteal phase | 84.2 (51.0 – 143.1) |
| Estrone Sulfate, pg/mL | |
| Follicular phase | 662 (299 – 1528) |
| Luteal phase | 1462 (574 – 3300) |
| Progesterone, ng/dL | 1404 (252 – 2748) |
|
| |
| Testosterone3, ng/dL | 23.5 (14.3 – 36.7) |
| Free testosterone3, ng/dL | 0.2 (0.1 – 0.4) |
| Androstenedione3, ng/dL | 100 (61 – 162) |
| DHEA, ng/dL | 615 (346 – 1130) |
| DHEAS, ug/dL | 87.9 (40.0 – 164.2) |
| SHBG3, nmol/L | 64.6 (32.0 – 116.5) |
| Prolactin3, ng/mL | 14.3 (8.1 – 27.4) |
| GH, ng/mL | 0.2 (0.1 – 4.0) |
| IGF-1, ng/mL | 240 (153 – 344) |
| IGFBP-3, ng/mL | 4813 (3823–5972) |
1
Among parous women only (n = 2213).
2
Abbreviations: BMI = body mass index; DHEA = dehydroepiandrosterone; DHEAS = dehydroepiandrosterone sulfate; SHBG = sex hormone binding globulin; GH = growth hormone; IGF = insulin-like growth factor; BP = binding protein
3
Average of follicular and luteal phase levels when available