Complete and selective estrogenic effects on lipids and cardiovascular disease.

Observational studies have shown a protective effect of estrogen replacement on risk of cardiovascular disease in postmenopausal women. The estrogen protection is thought to be mediated by mechanisms acting at different levels, including a beneficial effect on plasma lipid concentrations. Selective estrogen receptor modulators (SERM) share with estrogen the ability to reduce plasma levels of atherogenic lipoproteins like low-density lipoproteins and lipoprotein(a). The recent publication of the first randomized, placebo-controlled trial of estrogen/progestin replacement (HERS), which failed to show a reduced number of cardiovascular events in women randomized to estrogen treatment as compared with placebo, has cast some doubts on the protective role of estrogen. Other large randomized studies on the effect of estrogen and other compounds with estrogenic activity (eg, SERM) on cardiovascular disease risk are currently underway and will provide more definite answers to both clinicians and postmenopausal women.