Heart Disease in Women - Coronary Risk Factors

Dateline: 05/17/98

Heart Disease in Women is a very important, unique and exciting topic. This article is a part of a series that focuses on the special problems of Heart Disease in Women. You can find the others in the archives.

You can also review articles in the following interest areas dealing with heart disease:

• Minimally Invasive Heart Surgery
• MICAS website
• Fetal Heart Surgery
• Congenital Heart Disease

RISK FACTORS FOR CORONARY ARTERY DISEASE IN WOMEN

Heart disease mortality rates have been decreasing over the past several decades. However, the rate of decline is slower in women than in men. It is less in African-American women as compared to white women.

The magnitude of the problem

As women live longer, the aging population makes the absolute number of deaths due to cardiovascular disease (CVD) in women actually rise. In the year 2000 nearly 50 million American women will be older than 50 years. Because the risk of heart disease and stroke increases with age, there is a need for an increased awareness of the importance of CVD as a major public health issue for older women.

Cardiovascular disease, particularly coronary heart disease (CHD) and stroke, remains the leading killer of women in America and most developed countries. In 1994, the last year for which statistics are available, CVD claimed the lives of more than one half million women and accounted for 45.2% of all deaths in women, more than all forms of cancer combined ! The death rate due to CVD is 69% higher in black women than white women. It is estimated that 1 in 2 women will eventually die of heart disease or stroke, compared with 1 in 25 who will eventually die of breast cancer.

In this article, I will discuss recent advances in knowledge of the occurrence, determinants, and treatment of atherosclerotic CVD in women, including coronary artery disease, hypertension and stroke.

Women and Coronary Artery Disease

Women have a much lower risk of coronary artery disease than men. The risk of death due to CHD in women is roughly similar to that of men 10 years younger. However, as women have a higher likelihood of surviving to older ages, the actual number of deaths due to CHD are nearly equal in men and women.

In the Cardiovascular Health Study, the prevalence of heart attacks (myocardial infarction) in older women was 9.7% for those aged 65 through 69 years and 17.9% for those 85 years and older. What is more worrying from a public health perspective is that nearly two thirds of sudden deaths due to coronary artery disease in women in the Framingham Heart Study occurred in those patients with NO previous symptoms of heart disease. In contrast, almost one half of the men in that study had preceding signs or symptoms of heart disease. For these women, primary prevention is likely to be the only practical solution.

Risk Factors and Primary Prevention

Just as in men, the major risk factors for coronary artery disease in women are

* cigarette smoking
* high blood pressure (including isolated systolic hypertension)
* blood lipid disorders
* diabetes
* obesity
* sedentary lifestyle
* poor nutrition

However, gender differences have been documented, and I have discussed these in detail in another article.

Cigarette smoking

Cigarette smoking remains the leading preventable cause of coronary disease in women. More than one half of heart attacks among middle-aged women are attributable to tobacco. Risk of coronary events begins to decline within months of stopping smoking and reaches the level of persons who have never smoked within 3 to 5 years. Sadly, though, smoking cessation rates have declined more slowly among women than men.

The changing demographics of smoking, particularly the unfavorable smoking patterns among younger women, may contribute substantially to the future burden of coronary artery disease on women, as well as other smoking-related illnesses.

High Blood Pressure

Among US adults older than 45 years, 60% of white women and 79% of African-American women were classified as having hypertension (defined as either taking antihypertensive medication or having systolic BP over 140 mm Hg or diastolic BP over 90 mm Hg).

Of particular concern for older women is isolated systolic hypertension, which is estimated to affect 30% of women older than 65.

Lipid profile disorders

From 1980 to 1991 more than 50% of women older than 55 years had serum cholesterol levels that were considered high (over 240 mg/dL). A low level of high-density lipoprotein (HDL) cholesterol, however, was a risk factor for coronary artery disease in both younger and older women and was a stronger predictor of mortality related to heart disease in women than in men.

Obesity

The prevalence of obesity has increased among both men and women in the United States in the past decade; currently about one third of adult women (or 34 million) are classified as obese. Obesity, particularly abdominal adiposity, is an important risk factor in women.

Sedentary Lifestyle

Nearly 60% of both men and women have no regular physical activity. There may however be some element of bias in this observation, since most data are gathered by questionnaires which do not enquire about the amount of household work done by a woman. For instance, vacuuming two floors of a household consumes as much energy as playing nine holes of golf !

In any case, these findings support the 1995 federal exercise guidelines endorsing 30 minutes of moderately intense physical activity most days of the week, a program that should be feasible and safe for most of the population.

Diabetes

Diabetes is one of the most important gender-specific risk factors for coronary artery disease, and is associated with a threefold to sevenfold elevation in risk among women, compared with a twofold to threefold elevation among men; this gender-based difference may be due to a particularly deleterious effect of diabetes on lipids and blood pressure in women.

The epidemiological evidence is compelling: diets low in saturated fat and high in fruits, vegetables, whole grains, and fiber are associated with a reduced risk of coronary atherosclerosis.

Prevention of Coronary Events in Women

The use of drugs to control or reverse risk factors has proven successful to a variable extent. Anti-platelet therapy that aims to prevent platelets aggregating together and clogging coronary arteries is useful in some patients. Post-menopausal women benefit from hormone replacement with estrogens.

In primary prevention, the balance of benefits and risks of aspirin prophylaxis among women remains unknown and awaits the results of the ongoing Women's Health Study. Antioxidant vitamin supplements, particularly vitamin E, and homocysteine-lowering agents such as folate and B6, have promising roles in prevention of coronary artery disease, but conclusive evidence is still awaited. Early surgical menopause is linked to increased risk of coronary disease, which appears to be neutralized by the use of estrogen therapy.

In summary, clinical studies and trials provide compelling evidence that coronary artery disease is largely preventable. Pharmacological intervention has a role in primary prevention for selected patients. However, a major emphasis should be placed on lifestyle modifications, including smoking cessation, regular physical activity, maintenance of healthy weight, and consumption of a diet low in saturated fat and high in fruits and vegetables. Further studies on the potential benefits of stress reduction and psychosocial interventions can also provide valuable new information on heart disease prevention.

Next week : Diagnosis and Treatment of Coronary Artery Disease in Women.