Effect of Transdermal Estrogen Therapy on Bone Mineral Density in Postmenopausal Korean Women

OBJECTIVES To evaluate the effects of transdermal estrogen therapy on bone mineral density (BMD) in postmenopausal Korean women. METHODS A total of 149 healthy postmenopausal women were retrospectively evaluated: 100 were on hormone therapy (HT) and 49 were the control group. For the HT group, 54 applied estrogen transdermally using either a patch (n = 21) or gel (n = 33), and 46 took estrogen orally (conjugated estrogen 0.625 mg or equivalent). Demographic profiles and changes in BMD over two years were compared according to the route of the estrogen. RESULTS No differences were found in age, age at menopause, parity, body mass index, and type of menopause among the oral, transdermal and control groups. Compared with controls, HT significantly increased BMD after 2 years in both the lumbar spine and the total hip. The increases in BMD at both lumbar spine and hip were comparable between the oral and transdermal groups. There were also no differences in BMD changes according to progestogen addition in either the oral or transdermal groups. CONCLUSION Transdermal estrogen therapy increases BMD, comparable to oral estrogen, in postmenopausal Korean women.