Ask a woman what disease she fears most, and most likely she will answer “breast cancer.”But while breast cancer is a highly visible risk, heart disease is actually the leading cause of death among women of all ages. A woman is six times as likely to die from cardiovascular disease than from breast cancer.In fact, in every year since 1984, more American women than men have died from heart disease. This startling revelation has spurred two decades of careful study of the causes, symptoms, treatments and outcomes of heart disease in women. And this means that we now have critical information for women that will help keep them out of our operating rooms and catheterization laboratories.MORE: Family History of Heart Disease – What it Means for Your HealthThe media has overemphasized disparities between the sexes, creating the perception of vast differences between women and men when it comes to coronary heart disease (blockages in the heart’s arteries that can cause heart attacks). But the truth is that there are actually more similarities than differences between the sexes. Most important, women need to understand that the primary symptom of coronary heart disease, chest pain and the principal strategies for prevention and treatment—healthy lifestyle, medicine, angioplasty and surgery—apply equally to women and men.Estrogen and cardiac protectionUnfortunately, it is all too common for women and their doctors to ignore the threat posed by heart disease. The biggest mistake they make is to place too much faith in the power of estrogen. It is true that estrogen affords premenopausal women a certain amount of protection from coronary heart disease. This is one reason that, compared to young men, young women are less likely to get heart disease.Potentially beneficial effects of estrogen include decreased LDL cholesterol (the “bad” cholesterol), increased HDL cholesterol (the “good” cholesterol), blood vessel relaxation and protection of blood vessels from injury. Scientists believe that the combination of high circulating estrogen levels and a relatively low number of standard cardiac risk factors (smoking, high blood pressure, diabetes, high cholesterol) delay the appearance of coronary heart disease in most young women.But everything changes at menopause. Estrogen levels drop by 90 percent and the type of estrogen in the body changes, with most of the estrogen being produced by fat cells (estrone) rather than by the ovaries (estradiol). This major hormonal shift contributes to the increased risk for coronary heart disease that begins soon after menopause. By age 65 women catch up to men, achieving an unwanted equality as they develop heart disease at a rate equal to that of men of similar age.COLUMN: Why Heart Disease is Overlooked in WomenEstrogen replacement therapy (hormone replacement therapy) and the heartIf estrogen decline at menopause contributes to development of coronary heart disease, why not simply treat postmenopausal women with supplemental estrogen? Wouldn’t this protect their hearts, just like natural estrogen protects the hearts of younger women? Facing these questions in the 1990s, doctors did not wait for rigorous scientific studies to provide answers. They rushed for their prescription pads on the basis of compelling circumstantial evidence. For decades, doctors thought that taking hormones after menopause was helping the hearts of women. They were wrong.Large-scale studies conducted by the National Institutes of Health stunned doctors and their patients with the finding that hormone replacement therapy did not provide cardiac protection among older women. In fact, studies suggested that hormone replacement therapy could increase the risks of heart attack, stroke and breast cancer. These findings settled the question: postmenopausal women should not take estrogen or other hormones to try to ward off heart problems.MORE: Coronary Artery Disease – Get The FactsBut there is a role for hormone replacement therapy. Studies demonstrate that hormone replacement therapy can be used to relieve menopausal symptoms in women between 50 to 59 who are within 10 years of menopause. In these women, the risk associated with HRT is low, and the benefit in terms of quality of life may be substantial. Therapy should be started at the lowest possible dose, and patients should be weaned off the therapy as early as possible.Protect your heart: Our adviceMost coronary heart disease in women is caused by the same risk factors that affect men: smoking, high blood pressure, high cholesterol, diabetes, obesity, family history and advanced age. You can’t change your family history or your age, but you can control the other risk factors on this list. Don’t count on estrogen to protect you. Even a young woman can suffer a heart attack if she accumulates enough risk factors.MORE: Foods That Improve Your Genetic Heart Disease RiskPrevention begins early—right now. Make sure that you know your heart numbers, including your cholesterol values, blood pressure and body mass index (a measure related to body weight). Standard targets include LDL cholesterol less than 130, blood pressure 120/80 or less and a BMI between 20 and 25. Stick to a heart-healthy diet: we recommend a Mediterranean diet. Exercise daily. These are the steps to a healthy heart.