Objective: To determine whether the lowest available dose of percutaneous implant, 25 mg estradiol (E2), is effective for the prevention of postmenopausal bone loss.
Methods: Eighteen healthy postmenopausal women were treated with 25-mg percutaneous E2 implants for 1 year. Dual energy x-ray absorptiometry was performed at the lumbar spine and proximal hip using a quantitative digital radiography densitometer before treatment and after 1 year. Estradiol and FSH were also measured before and after 1 year of treatment. The changes in bone mineral density were compared with a matched reference group of 18 women who did not wish treatment.
Results: The median percentage changes in the treated group after 1 year were 5.65% at the lumbar spine, 3.38% at the femoral neck, and 3.36% total hip. At 1 year, there was a significant increase in bone mineral density from baseline at all sites measured except Ward triangle. The median post-treatment E2 level was 320 pmol/L (range 114-813), and FSH was 28 IU/L (range 2-66).
Conclusion: This study demonstrates that 25-mg percutaneous E2 implants significantly increase bone mineral density at the spine and hip in postmenopausal women. This dose is effective to prevent postmenopausal bone loss.