Can HRT reduce the chance of my developing heart disease? i-checksum="31721" ends

Authors:

Samsioe G.

Institution:

Department of Obstetrics Gynecology, Lund University Hospital,S-221-85 Lund; Sweden.

Title:

Cardioprotection by hormone replacement therapy (1995-624).

Source:

Contemporary Reviews in Obstetrics and Gynaecology. Vol 7(2) (pp18-124), 1995.

Abstract:

In line with the clinical observation that below the age of 55 years cardiovascular disease is less common in women than in men, observational studies on oestrogen replacement therapy to postmenopausal women suggest a reduction of cardiovascular disease irrespective of end-point. Results from over 30 observational studies of both case-control and cohort-design indicate that the risk of myocardial infarction may be halved in women using oestrogen replacement therapy. Given the large number of observational studies comprising several thousand women studied for 10 years or more, it has been possible to exclude several confounders and reduce substantially potential biases. The protection in women carrying risk factors for cardiovascular disease seems to be even greater. In women with a sustained myocardial infarction the relative risk may be as low as 0.2. Observational data including data concerning oestrogen-progestogen combinations are few and more data are urgently needed, but results of published data do not suggest any marked attenuation by the addition of progestogen to oestrogen replacement therapy in cardioprotection. The results of coronary angiography and oestrogen replacement suggest a reduction of coronary stenosis most marked in those with severe stenosis. Based on these observations it is suggested that cardioprotection by oestrogens is conferred by at least two major mechanisms, i.e. an influence on the artherosclerotic process and on arterial wall function. Blood pressure, haemostasis, insulin resistance and scrum lipid and lipoprotein profile are all influenced in a direction of reduced risk of artherosclerosis. In addition, oestrogens may lower lipoprotein (a) and reduce oxidation of low-density lipoproteins. Arterial wall function may be influenced by the ability of oestrogens to act as a calcium channel blocker, to reduce endothelin levels and to downregulate endothelin receptors. Some data also imply that the thromboxane/prostacyclin ratio is favourably influenced. Other factors, some of which may be linked to nitrous oxide metabolism may also be favourably influenced. But severalQuestions remain. Dose and duration relationships have not been outlined in detail and conjugated e quine oestrogens have been used as the predominant oestrogen. Different oestrogens including mode of administration as well as the role of various progestogens need to be further explored in observational as well as in experimental studies.