Because cardiovascular disease (CVD) is the most important cause of death in women in the United States, it is imperative that the main risk factors for CVD in women be identified and modified. The risk factors that have the strongest impact on the incidence of CVD in women are not necessarily the same as those for men. The risk for women increases at menopause, most likely because of the decrease in levels of circulating estrogen. The classic risk factor for CVD is altered lipid levels. In middle-aged women, elevated low-density lipoprotein cholesterol levels are somewhat less important relative to lowered levels of high-density lipoprotein cholesterol and elevated triglyceride levels as independent risk factors. The metabolic syndrome, which encompasses a range of conditions known to be CVD risk factors, also has a greater impact on the incidence of CVD in women than in men. Various emerging risk factors appear to be important indicators for vascular disease in women, including C-reactive protein, homocysteine, and lipoprotein(a) levels. Many of these risk factors are affected by hormone replacement therapy, which may diminish CVD risk in postmenopausal women. Because of the complex origin of CVD, it is important to target the full array of risk factors for modification, rather than focusing on a single factor or treatment to the exclusion of other important markers.

Hormone replacement therapy (HRT), used by many women to relieve the symptoms of menopause and for the prevention of osteoporosis, is available in an increasing number of formulations. Options include various combinations of estrogen and progestin as well as different routes of administration. For women with a uterus, who require a progestin, a convenient and commonly used option is combining the estrogen and progestin in a single pill. Such formulations have the lipid-modifying effects of estrogen, altered to specific type and dose of progestin used. The cardioprotective increases in levels of high-density lipoprotein cholesterol associated with exogenous estrogen may be blunted or even reversed with certain HRT regimens. In addition, some progestins minimize the increase in triglycerides that occurs with exogenous estrogen, whereas others do not. Because of the importance of lipid markers as risk factors for cardiovascular disease in postmenopausal women, these lipid effects should be carefully considered when selecting an HRT regimen.