Estrogen, hormonal replacement therapy and cardiovascular disease

Premenopausal women have a lower risk and incidence of hypertension and cardiovascular disease (CVD) compared to age-matched men and this sex advantage for women gradually disappears after menopause, suggesting that sexual hormones play a cardioprotective role in women. However, randomized prospective primary or secondary prevention trials failed to confirm that hormone replacement therapy (HRT) affords cardioprotection. This review highlights the factors that may contribute to this divergent outcome and could reveal why young or premenopausal women are protected from CVD and yet postmenopausal women do not benefit from HRT.

In addition to the two classical estrogen receptors, ERα and ERβ, a third, G-protein-coupled estrogen receptor GPR30, has been identified. New intracellular signaling pathways and actions for the cardiovascular protective properties of estrogen have been proposed. In addition, recent Women's Health Initiative (WHI) studies restricted to younger postmenopausal women showed that initiation of HRT closer to menopause reduced the risk of CVD. Moreover, dosage, duration, the type of estrogen and route of administration all merit consideration when determining the outcome of HRT.

HRT has become one of the most controversial topics related to women's health. Future studies are necessary if we are to understand the divergent published findings regarding HRT and develop new therapeutic strategies to improve the quality of life for women.