Long-term effects of percutaneous estradiol on bone loss and bone metabolism in postmenopausal hysterectomized women

Objective: To determine whether percutaneous estradiol (pE₂) (1.5 mg/day) is able to counteract the postmenopausal bone loss in postmenopausal hysterectomized women, in a double-blind study versus oral estriol (E₃) (2 mg/day). Methods: The bone mineral density of the lumbar spine (LS) and of the proximal femur (PF) was measured every 3 months by dual energy X-ray absorptiometry for 2 years in 43 hysterectomized postmenopausal women (21 in the E₂ group and 22 in the E₃ control group), and in a subset of patients for a 3rd year. The statistical analyses were performed on Macintosh using StatView II^TM. Results: A significant bone loss of 1.2 (0.4)% and of 1.3 (0.3)% per year was observed in the control group, respectively at LS and at PF, versus a significant gain of 1.2 (0.5)% per year in the treated group at the LS. No significant change at PF occurred in the treated group. In the 20 patients followed up for a 3rd year on pE₂, an increase of 1.2 (0.9) and 2.5 (1.4)% at LS in the 12 former active group patients and the eight formerly control patients, respectively was seen. The same trend was observed at the proximal femur. Conclusion: pE₂ (1.5 mg E₂) is able to counteract the postmenopausal bone loss in hysterectomized women, whereas E₃ (2 mg/day administered orally) is unable to maintain bone mass.