Long-term postmenopausal hormone replacement therapy effects on bone mass:differences between surgical and spontaneous patients

Background: Hormone Replacement Therapy (HRT) begun soon after spontaneous menopause or oophorectomy minimizes or even reverses the loss of bone that occurs normally during those years. The persistence of this HRT protective effect at long-term on bone density, however, is not well documented. Aim: to evaluate the effects of 5 years of HRT in postmenopausal women on bone m ineral density of the lumbar spine. Subjects and Methods: The 5-year prospe ctive study enrolled 154 postmenopausal women, of them 136 completed the fi rst year and were considered electible to continue the follow-up. These 136 postmenopausal women were allocated to two groups according their origin: surgical (n = 68) and spontaneous (n = 68). HRT was prescribed and bone min eral density (BMD) was measured at the lumbar spine prior to commencement o f therapy, and then yearly for the duration of the study. All patients rece ived a continuous therapy with standard dose (0.625 mg/day) of conjugated e quine estrogen (CEE) or 50 mu g/day of 17-beta-Estradiol in transdermal the rapeutic systems (TTS). Subjects who experienced natural menopause also rec eived 5 mg/day of medroxyprogesterone acetate sequentially added to the las t 12 days of estrogen therapy. Treated groups were compared with two non-tr eated control groups (surgical n = 77; spontaneous n = 53). Results: Our da ta showed that HRT increased the BMD of women who had experienced spontaneo us menopause. Comparison with a control group revealed that HRT also protec ted against bone loss in women who had undergone surgical menopause. Conclu sion: Long term hormone replacement therapy increases bone mineral density in women who have experienced natural menopause, and protects against bone loss in surgically postmenopausal women. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.