Hormonal Update Volume 3 Number 7
Matters of the Heart
Cardiovascular Disease and Your Hormones
Heart disease has long been considered a man's disease, but that is no longer true. It is now the number one killer of women. In fact, if a woman has a heart attack she is two times more likely to die from it than a man. Women are ten times more likely to die of heart disease than breast cancer. Even worse, one out of every two women will likely die of heart disease.
Unlike the symptoms of a man's heart attack - sharp pain in the chest that radiates down the left arm - women can experience aching or pain in the chest, neck, jaw, back or shoulders, nausea, fatigue, dizziness, shortness of breath, or indigestion. Often these symptoms seem so benign they are ignored, mistaken for something else, or even misdiagnosed. However, it isn't just the symptoms of heart disease that are dissimilar for men and women. Their very hearts are different.
A woman's heart is smaller than a man's, and her heart beats faster, even during sleep. It also takes a woman's heart longer to relax after each beat. A man's arteries are more rigid and pipe-like than a woman's. The arteries of a woman's heart are soft and more flexible. According to a leading heart surgeon only thirty percent of women who have heart attacks have calcium deposits in their arteries, ninety percent of men do.
Diet, exercise, smoking, diabetes, stress, and family history all play a role in whether or not a woman is at risk for cardiovascular disease (CVD). Yet, even if a woman avoids all of the risk factors, as she approaches menopause and her hormones decline her chance of developing heart disease goes up substantially. Her risk of stroke, also a leading cause of disability and death in women, goes up as well. Statistics show that one in every ten women between the ages of forty-five and sixty-four has heart disease. This suggests that more youthful hormone levels may be heart protective. In fact, they are. Hormones play a very important role in the health and functioning of a woman's cardiovascular system. In this Hormonal Update we take a look at hormones and your heart.
A Woman's Natural Estrogen
The estrogen a woman's body produces naturally has an antioxidant action, which protects the lining of her arteries from free-radical damage. This helps to keep the arteries flexible and open so blood flows freely through them. Estrogen also helps increase the level of high-density lipoprotein (HDL) or good cholesterol in the blood. Having enough HDL in the blood helps protect the inner lining of blood vessels from plaque formation. It also facilitates the removal of the plaque forming low-density lipoproteins or LDLs. Less plaque means less clogging; less clogging means lower risk of heart attack and stroke. Estrogen also reduces the amount of fibrinogen in the blood. Fibrinogen is a key component in blood clotting.
Numerous studies have shown that estrogen replacement protects the cardiovascular system and at the same time has a neuroprotective effect. For example, the carotid artery often thickens after menopause. This thickness decreases with estrogen replacement. The estrogens also appear to enhance cerebral blood flow and reduce the risk of stroke.
The Controversy about HRT and Heart Disease
The Women's Health Initiative is a formidable, fifteen year, multi-million dollar investigation into the most common causes of death, disability and impaired quality of life in postmenopausal women. Comprised of over 160,000 women, ages fifty to seventy-nine, it is one of the largest U.S. studies of its kind. A state-of-the-art, multifaceted clinical trial, WHI is examining hormone replacement therapy, dietary patterns, and calcium/vitamin D supplements and their effects on the prevention of heart disease, cancer and osteoporosis.
Recently, WHI ended one phase of their research prematurely due to findings suggesting increased risk for breast cancer and heart disease. It was the phase of the trial consisting of a single dose tablet of Prempro™, a combination conjugated estrogen and progestin. Progestin is a synthetic version of progesterone. Synthetic hormones do not match the molecular structure of the hormones your body produces naturally. They are similar, but not identical.
Another scientific trial, the Postmenopausal Estrogen Progestin Intervention Study (PEPI), found that estrogen combined with natural progesterone significantly improved a woman's cardiovascular lipid profile. It also found that synthetic progestin, such as that used in Prempro, did not demonstrate the same benefit. It seems apparent that synthetic and natural, bio-identical progesterone act differently in the body.
Interestingly, it is not widely reported that the segment of the WHI trial that was ended was only one arm of the research. The segment of the study examining the use of estrogen alone is ongoing. Moreover, estrogen only use has not demonstrated the same risks. Nor is it common knowledge that significant "good news" has resulted from WHI - a 37% reduction in colorectal cancer, a 33% decrease in hip fractures, and a 24% decrease in fractures in other bones. Also, there have been no measurable differences found in total mortality between HRT users and those receiving the placebo.
Before you Abandon HRT
When reading a scientific study about hormones it is important to remember that the study participants may be different from you. You can more fully understand the true impact of a study when you know the demographic of the participants, hereditary factors, ethnicity, (some ethnic groups are more prone than others to certain diseases) and the nature and dosage of the hormone being used.
The benefits of hormone replacement therapy are many. Symptomatic relief of menopausal symptoms, decreased risk for osteoporosis, colon cancer, tooth decay and even Alzheimer's disease are among them. And there are many studies that support the use of estrogen replacement to decrease a woman's risk for heart disease.
If you are considering hormone replacement therapy remember that you are an individual. Determining your hormone levels before you start aids your doctor in prescribing the right hormone in the right dose for you. In addition, monitoring your hormone levels regularly can help establish how well your HRT is working for you.
Hope for the Future
When it comes to hormones and our health our true hope for the future is continued scientific investigation. A hot area of hormone research is how hormones impact the brain. (See Hormonal Update Volume 2 Numbers 10 and 11.) New studies have shown that hot flashes may be bad for the brain. Using a non-invasive imaging technique called SPECT researchers found that women who were running on estrogen empty had decreased blood flow through the brain even when they were cool and calm. During a hot flash blood flow became even more compromised. Worse yet, the vascular changes seen in these women mirrored those of patients with mild to moderate Alzheimer's disease.
Another recent discovery has shown that a family history of CVD or personal history of hypertension can lead to an exaggerated blood pressure response to mental stress. Women matching this profile who were on HRT, however, did not have this response when confronted with a stressful situation. Contrarily, at risk women who were not taking hormones, who experienced rage fairly regularly in response to stress, demonstrated three times the increase in blood pressure as their HRT using counterparts.
Regarding breast cancer, it has been shown that women who develop breast cancer while on HRT have a better prognosis than women who have never taken it. New studies are also showing that women may need androgens, too - for bone, heart, and brain health.
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