Table 2.
Baseline Serum Levels of E2 and SHBG According to Quartiles of FEI in Postmenopausal Women in a Prospective Case-Control Study of Incident Stroke From the Study of Osteoporotic Fractures
| Mean (SD) | ||
|---|---|---|
| FEI Quartilea | E2 Concentration, pg/mL |
SHBG, µg/mL |
| Quartile 1 | 4.4 (1.3) | 6.9 (1.7) |
| Quartile 2 | 5.6 (1.4) | 4.9 (1.3) |
| Quartile 3 | 8.0 (2.5) | 4.3 (1.4) |
| Quartile 4 (highest) | 10.9 (4.8) | 2.7 (1.1) |
Abbreviations: E2, total estradiol; FEI, free estradiol index; SHBG, sex hormone–binding globulin.
SI conversion factors: To convert E2 to picomoles per liter, multiply by 3.671; SHBG to nanomoles per liter, multiply by 8.896.
a
The FEI was calculated by dividing E2 concentration (in picomoles per liter) by SHBG concentration (in nanomoles per liter): quartile 1=0.096 to 0.373, quartile 2 ≥ 0.373 to 0.612, quartile 3 ≥ 0.612 to 0.952, and quartile 4 > 0.952.