Postmenopausal hormone replacement therapy and cardiovascular system

Women suffer from cardiovascular diseases 10 years later than men, therefore female sex has been considered to be a ‘protective factor’. However, the risk in women increases rapidly after menopause and the declining levels of endogenous estrogen is thought to be responsible. Postmenopausal hormone replacement therapy (HRT) decreases the severity and intensity of menopausal symptoms and improves women’s quality of life. Until the last 10 years, based on the results of observational studies, postmenopausal HRT was thought to protect women against cardiovascular events and decrease the risk of coronary artery disease by 35-50%. However, recent randomized primary and secondary prevention trials did not support the cardioprotective effect of HRT. The different results of observational and randomized controlled trials are discussed to be related to the differences in the study population. The study population in observational and prospective cohort studies included relatively young women at the earlier stages of menopause, whereas studies showing neutral or negative effects of HRT included women older than 50 years old at least 10 years in menopause. Furthermore, the effects of estrogen depend on the state of vascular pathology. In relatively healthy vessels with no or early signs of atherosclerosis, estrogen prevent the development or progression of atherosclerotic lesions, whereas in the presence of established atherosclerotic lesions, estrogen promotes atherosclerosis or may even trigger acute events. Therefore, it is critically important to predict which women can safely receive HRT and which are at increased risk from HRT. Under the light of current knowledge, HRT should not be used for prevention from cardiovascular disease in postmenopausal women and the many other preventive strategies, (diet, exercise, blood pressure or cholesterol control) that are proven to be effective but underused, should be kept in mind.