Lipids and cardiovascular disease: do the findings and therapy apply equally to men and women?

Abstract

Dyslipoproteinemia is prevalent in women as well as in men. In both, its consequences--premature atherosclerosis and CAD morbidity and mortality--are more common. Although clinical evidence of the benefits of cholesterol lowering is less abundant in women, it is not entirely absent. As in men, cholesterol lowering in women is associated with a decline in CAD risk and with regression of coronary atherosclerosis. Lipoprotein risk factors have some special characteristics in women. Low-density lipoprotein cholesterol may be a less important risk factor in women, perhaps because estrogen protects the arterial wall against LDL deposition. High-density lipoprotein cholesterol is a better predictor of risk in women than in men. Triglycerides are an independent predictor of CAD risk in postmenopausal women. The effects of endogenous gonadal hormones in life-cycle changes in women is evident. As girls pass through puberty, HDL-C levels do not fall as they do in boys of the same age. In pregnancy, LDL-C, HDL-C, and triglyceride levels all rise. However, LDL-C stays elevated until well after delivery, whereas triglycerides fall to baseline at about the time of delivery, and HDL-C levels begin to fall at about 24 weeks. Interestingly, this fall in HDL-C is not accompanied by a fall in apoA-I levels, implying a change in HDL composition during the latter portion of pregnancy. After menopause, LDL-C levels rise sharply, whereas HDL-C levels decline modestly. Again, this decline in HDL-C is accompanied by a rise in apoA-I levels, implying a change in HDL composition. Diet, weight loss, and exercise are less effective in altering lipoprotein levels in women than in men. The reasons for this are not clear, although it is reasonable to speculate that endogenous gonadal hormones play a role. Genetic dyslipoproteinemia occurs in women, although the effect on CAD rates may be mitigated by the generally higher levels of HDL-C enjoyed by women. Exogenous hormones in the form of OCs and postmenopausal HRT affect circulating lipoprotein levels according to their composition. Generally, estrogens have favorable effects, raising HDL-C and lowering LDL-C levels. Progestins are either neutral or oppose estrogen effects, depending on their dose and androgenicity. Use of modern OCs probably does not adversely affect CAD risk except in combination with cigarette smoking. However, HRT has a strong favorable effect on CAD risk when unopposed estrogen is used, probably due to increases in HDL-C levels.(ABSTRACT TRUNCATED AT 400 WORDS)

PIP: Heart disease is the number 1 cause of death among women in the US, yet health providers, the public, women's health organizations, and women overlook this fact. Risk factors and the progression of cardiovascular disease (CVD) are different in women than in men. For example, women are more likely to develop and succumb to heart disease at more advanced ages than men. This may be due to the protective effect of estrogen that occurs to at least middle age when menopause occurs. The clinical studies examining means to prevent CVD in the 1960s and 1970s basically included only middle aged or older men. Yet scientists have since learned that reproductive hormones do not allow them to extrapolate the results of these studies to women. For example, some interventions identified in those trials do not as effectively affect lipoprotein levels in women as they do in men. These interventions include diet, weight loss, and exercise. Instead, cholesterol screening and management, hormone replacement therapy for cardiovascular indications, and public health messages promoting a low fat diet can be effective in women. As is the case with men, women often have a genetic predisposition for dyslipoproteinemia. High density lipoprotein cholesterol is a more significant CVD risk factor in women than in men while low density lipoprotein is more significant in men than in women. Even though estrogen therapy may prevent heart attacks, its price may be too high since it increases the risk of breast cancer. Many obstetrician-gynecologists feel confident of their ability to screen for cholesterol, yet they are not as confident in their ability to provide dietary counseling or managing drug therapy.