Short- and long-term effects of hormone replacement therapy on cardiovascular risk factors in postmenopausal women.

ABSTRACT

BACKGROUND: The beneficial effect of hormone replacement therapy (HRT) on cardiovascular disease has been documented in postmenopausal women, but has a significant time trend. Thus, it is worthwhile to further study whether there are different effects on cardiovascular factors between short- and long-term use of HRT. METHOD: Prospective study of the changes on lipoprotein profile, hemostatic factors, and platelet aggregation was evaluated in 21 postmenopausal women receiving oral E2 valerate (2 mg/d) combined with medroxyprogesterone acetate (10 mg/d) during the last 10 days of each 21-day cycle. The treatment period was 24 months. RESULTS: During the 24 months of treatment, total cholesterol, low-density lipoprotein cholesterol (LDL-C), and atherogenic indices- total cholesterol-to-high-density lipoprotein cholesterol (HDL-C) and LDL-C-to-HDL-C, were significantly reduced. The concentrations of tissue plasminogen activator and plasminogen activator inhibitor-1 were significantly reduced after 12 months of HRT. In addition, the concentrations of antithrombin III were significantly increased, but protein S was statistically decreased during the 18 months of HRT. The maximum aggregation and slope of platelet aggregation were significantly reduced only during the first 12 months of HRT. CONCLUSION: This study demonstrates that there were some differences in cardiovascular risk factors between short- and long-term HRT, especially in changes in platelet aggregation and hemostatic factors. However, the long-term favorable effect on lipoprotein metabolism and fibrinolytic activity among hormone users may explain, in part, the inverse association between HRT and cardiovascular disease.