[Hormone replacement therapy]

Hormone Replacement Therapy (HRT) is replacement of depleted endogenous estrogen for postmenopausal women. Usually progestin is used in combination to avoid endometrial proliferation. As for bone metabolism, estrogens exert bone protective effect through inhibition of bone absorption. HRT has been shown to improve bone mineral density and to lower the risk of osteoporotic bone fracture. However, the results of recent large scale clinical studies in the U.S. indicate that HRT not only raise the risk of breast cancer, but also increase the incidence of atherosclerotic cardiovascular diseases. According to these studies, the benefit of HRT does not outweigh its risk except the treatment of postmenopausal vasomotor symptoms. To resolve this problem, low dose HRT and SERM (selective estrogen receptor modulator) regimens are under investigation.