Lipid and lipoprotein changes in relation to oral contraception and hormonal replacement therapy

Abstract

Estrogens and progestins for contraception or hormonal replacement therapy are widely used by practitioners. These steroids have substantial effects on lipids and lipoproteins that appear to be primarily related to chemical structure of the compound, dosage, and a patient's hormonal status. Although the mechanisms by which alterations in lipid and lipoproteins affect atherogenesis are not fully understood, epidemiologic studies clearly associate alterations with risk of coronary heart disease. Attention to these alterations by progestins and estrogens, as well as further research on how these steroids may exert other cardiovascular effects, is important because atherosclerotic heart disease is a major cause of morbidity and mortality for women as they age.

PIP: The use of estrogens and progestins for contraception for hormonal replacement therapy has substantial effects on lipids and lipoproteins. Elevations of lipoproteins such as total cholesterol, low density lipoprotein (LDL)-C, and apoprotein B, and reduced levels of others such as high density lipoprotein (HDL)-C and apoprotein A-1, are associated with increased risk of coronary heart disease, although the exact mechanism by which such changes contribute to atheroma formation is unknown. The effect of an estrogen or progestin on the lipid profile is dependent on the chemical structure, dose, and route of administration as well as the hormonal status of the patient. Moreover, when an estrogen and progestin are combined in a therapeutic regimen, additional interactions occur that further complicate understanding of this process. Some epidemiological studies have suggested that mechanisms other than those closely associated with the lipid/lipoprotein system may be operant in the development of coronary heart disease and that the protective effects of estrogen far outweigh any adverse effects of progestin. Other studies have found an increased risk of coronary heart disease among past oral contraceptive users. Since atherosclerotic heart disease is a major cause of morbidity and mortality for women as they age (a cumulative mortality for women 55-75 years of age of 10,500/100,000), further research on the effects of steroids on cardiovascular factors is urgently needed.