After reading these articles, the reader should be able to discuss the epidemiology of coronary heart disease in women and evidence from clinical trials on the efficacy of cholesterol-lowering therapy in primary and secondary prevention of coronary events, Cholesterol Lowering in Women article.
Amid growing recognition that cardiovascular disease is the leading cause of death for women in the United States,1 an increasing body of data is emerging on differences and similarities in coronary heart disease (CHD) in men and women. In addition, treatment options for cardiovascular risk reduction in women have been clarified, Cholesterol Lowering in Women article.
Disruption of the cholesterol plaque in a coronary artery is central to the development of symptomatic CHD in both women and men, but mechanisms of plaque disruption and stabilization may differ. Women may be more likely to develop plaque erosion than plaque rupture,2 and the acute coronary syndrome in women is more likely to present as unstable angina than as acute myocardial infarction (MI).3 Another difference between the sexes is that epidemiologic studies show a strong relationship between low-density lipoprotein (LDL) cholesterol levels and cardiovascular risk in men,4 but the association between LDL cholesterol levels and cardiovascular mortality may be less in women5 , Cholesterol Lowering in Women article.
Epidemiologic studies show that hormone replacement therapy (HRT) in women reduces LDL cholesterol levels by approximately 10%, increases high-density lipoprotein (HDL) cholesterol levels by approximately 10%, and reduces the risk for cardiovascular events.6-9 The National Cholesterol Education Program (NCEP) guidelines9 used epidemiologic data on HRT for recommendations for lipid lowering in women. Until recently, however, clinical trial data were not available on primary or secondary cardiovascular event reduction in women with either conventional lipid-lowering therapy or HRT. More than 50 million women in the United States have total cholesterol levels greater than 200 mg/dL,10 the desirable blood cholesterol level according to NCEP guidelines.9 Lipid levels in women increase with age. In women less than 45 years of age, total cholesterol levels average 185 to 207 mg/dL, whereas in women between 45 and 65 years of age, they increase to 217 to 237 mg/dL, similar to levels in men. Beyond age 70, average total cholesterol levels in women exceed those in men.1112 In parallel with this gradual rise of cholesterol levels with age, women develop cardiovascular disease, on the average, 10 years later than do men. The increase in lipid levels near menopause and the delay in onset of disease symptoms in women can be attributed to a protective effect of estrogens. Premenopausal women, with the exception of high-risk women with diabetes or strong risk-factor profiles for cardiovascular disease, are at lower risk than men for the development of CHD. Overall, 26% of American women have lipid levels that qualify for diet or drug therapy to reduce cardiovascular risk. Among those more than 55 years of age, the number rises: 51% of women 55 to 64 years old and 54% of women 65 to 74 years old qualify for lipid-lowering therapy, Cholesterol Lowering in Women article.

Women have been excluded from clinical CHD trials because of childbearing capacity, advanced age at onset of disease, and the seemingly better prognosis for women with angina.13 Because of a lack of clinical trial data on primary and secondary cardiovascular risk reduction in women, evidence-based recommendations have been extrapolated from data in men. Studies of lipid-lowering therapy in women with documented CHD, however, show marked undertreatment of women, despite the treatment guidelines.14 Differences in characteristics of CHD in women and lack of specific data on lipid-lowering therapy in women have contributed to the undertreatment of women with documented CHD.
A growing body of evidence now exists for both primary and secondary cardiovascular risk reduction in women using the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins). Four statin trials in a cross-section of women, with and without established CHD, have demonstrated prevention of acute coronary events. In contrast, despite large bases of epidemiologic data suggesting event reduction with HRT and basic scientific research showing the beneficial effects of HRT on the arterial wall and coronary plaque, the only prospective trial of HRT in women with established CHD did not show reduction of cardiovascular events, Cholesterol Lowering in Women article. (1)