Menopause and post-menopause

From the endocrine point of view, menopause is considered a deficiency state and oestrogen therapy regarded as restoring the pre-menopausal endocrine milieu. Oestrogen therapy alleviates acute climacteric symptoms and also reduces the risk of cardiovascular disease, osteoporosis and Alzheimer's disease. Cardiovascular protection seems to be the major benefit of oestrogen replacement: it reduces morbidity and mortality from coronary heart disease by approximately 50%. The mechanisms are complex and not fully understood. In this review we discuss currently available data on the effects of hormone replacement therapy on serum lipids and lipoproteins, the vessel wall (endothelium dependent and endothelium independent), blood flow, cardiac function, blood pressure, haemostasis, insulin sensitivity and direct anti-atherosclerotic effect as possible mechanisms of cardioprotection. Oestrogen therapy reduces the rate of post-menopausal bone loss, increases bone mineral density (BMD) and decreases fracture rate. Recent evidence suggests that initiation of oestrogen therapy in older women produces larger increases in BMD which might provide a significant protective effect at the time when fracture is common. The incidence of Alzheimer's disease is reduced by 50% in post-menopausal women taking oestrogen replacement. Limited clinical trials of oestrogen treatment in women with this disease have documented beneficial effects on cognitive function. The results of epidemiological studies of the effects of oestrogens on breast cancer risk are conflicting but recent evidence suggests that the risk is increased in current users after 5 years of use and among older women. In contrast, increase in the risk of venous thromboembolism is most significant within the first 12 months of therapy, strongly suggesting the importance of individual susceptibility.