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Estrogen, HRT and The Heart

Estrogen is a major female sex hormone that is crucial to a woman’s development, ability to bear children and overall health. It is the hormone responsible for monthly menstruation and many changes throughout a woman’s life. Around the age of 50, the level of estrogen and other adrenal hormones such as progesterone begin to decline, and a woman stops menstruating. This time, known as menopause, is marked by a significant decrease in the amount of sex hormones produced by a woman’s body.

Estrogen appears to have a number of potent health benefits, including protection from heart disease and osteoporosis. Thus, when a woman enters menopause, her risk of heart disease begins to increase.

Hoping to recapture the benefits of estrogen for women in menopause, physicians began recommending Hormone Replacement Therapy (HRT) with synthetic estrogens for post-menopausal women.

Benefits of Estrogen

There are three types of estrogen: estrone (E1), estradiol (E2) and estriol (E3). Normal concentrations of estrone are produced in body fat.

Estrogen protects premenopausal women in a variety of ways.

  • Blood Vessels: The blood vessels that supply the heart with blood have estrogen receptors that are sensitive to the effects of estrogen. The estrogen molecule can provoke reactions in the blood vessels. These reactions include controlling the growth of smooth muscle in the walls of the blood vessels, which helps them remain open and reduces the risk of atherosclerosis (“hardening” of the arteries).
  • Cholesterol: Estrogen also appears to increase the level of “good” (high-density lipoproteins or HDL) cholesterol and decrease the level of “bad” (low-density lipoproteins or LDL) cholesterol.
  • Brain Cells: Estrogen may help to prevent the gradual decline of brain cells in four ways. First, it has an effect similar to antioxidants which block the harmful effects of oxygen free radicals. Second, it has effects similar to anti-inflammatories, which may help prevent the inflammation of the brain tissue that is often seen in Alzheimer’s patients. Third, it promotes the growth of both nerve pathways and nerve cells that release acetylcholine (ACh), which is an important chemical messenger (neurotransmitter). Fourth, estrogen appears to prevent one of the main causes of Alzheimer’s (beta-amyloid peptides) from being manufactured in the body.
  • Bones: Estrogen may help to protect bones by maintaining a healthy balance between bone creation and bone resorption. After menopause, women tend to lose bone faster than they rebuild it, which can lead to decreased bone mineral density and osteoporosis. Estrogen has been shown to protect bone mineral density, thus reducing the risk of suffering from osteoporotic fractures, which are a major source of disability among post-menopausal women.

Hormone Replacement Therapy

As its name suggests, Hormone Replacement Therapy (HRT) involves the replacement of the sex hormones that are lost during menopause. HRT helps reduce symptoms experienced by women during and after menopause. It also helps prevent certain diseases (e.g., osteoporosis, colon cancer).

HRT may be taken in various forms, including pills, skin patches, vaginal creams, vaginal rings, suppositories or injections. The method of delivery may depend on the nature of the patient’s symptoms.

Women should not take HRT drugs in either form if they have the following health conditions:

  • History of stroke or heart attack
  • History of blood clots
  • Pregnancy
  • Cancers of the breast or uterus
  • Liver disease

HRT and the Heart

A pair of major studies was launched to study the effects of estrogen on heart disease in women. Known as the Women’s Health Initiative (WHI), these two studies did not measure the effect of estrogen on side effects of menopause. Instead, they considered only estrogen’s effect on the cardiovascular system. The first of the two studies looked at combination estrogen/progestin therapy in 16,000 postmenopausal women aged 50 to 70 who still had their uteruses. The second looked at estrogen-only therapy in 11,000 women who had no uteruses (and therefore did not need to take progestin).

When it was shown that the risks of HRT outweighed its benefits. Researchers found that HRT increased the risks of heart attack, stroke, breast cancer, blood clots and overall cardiovascular disease. No protective effect was noticed when it came to Alzheimer’s disease and cognitive function. These findings overwhelmed the therapy’s protective effect against fractures and colon cancer. A separate study conducted by British researchers supported these results, adding that – for women in their 50s taking HRT for five years, breast cancer is the greater risk. Those in their 60s have a higher risk of stroke or pulmonary embolism.

The reaction to this news was rapid and widespread. Between 1995 and 2001, the percentage of women aged 50 to 74 taking some form of HRT increased from 33 percent to 42 percent. By 2003, after the first of these results had been published, that number dropped to 28 percent. Overall, hormone therapy prescriptions dropped 38 percent in the first year after the study’s findings were published. Today, neither estrogen/progestin therapy nor estrogen-only therapy is recommended for the prevention of heart disease, osteoporosis or Alzheimer’s disease. However, HRT may still be recommended on short-term basis to control a variety of menopausal and post-menopausal symptoms.

The risk for heart disease and stroke varies with age and the overall health of a woman. Consultation with one’s physician is essential to weigh the family and person medical history, as well as potential risks and benefits with HRT over the short and long term. 

Alternatives to HRT

A number of alternatives to traditional hormone replacement therapy (HRT) are available to patients, including:

  • A fairly new class of estrogen-like drugs is being designed to offer postmenopausal women the benefits of HRT without any harmful effects on the reproductive organs. These compounds are called selective estrogen receptor modulators (SERMs). They are designed to specifically target the areas of the body that require protection and to avoid the areas of the body that would be harmed by HRT.
  • Low-dose estrogen and HRT is available through patches that are changed approximately weekly. Estrogen doses as low as 0.014 milligrams (mg) have been approved for the prevention of osteoporosis. Transdermal patches can also deliver low-dose progestins for the relief of hot flashes. 
  • There are some herbal and other non-prescription strategies for dealing with both perimenopausal changes and the higher risks associated with postmenopause. Among the most common of these is the use of soy supplements, which contain chemicals that are chemically similar to estrogen (e.g., phytoestrogens). However, unlike prescription drugs, the health claims made by manufacturers of these preparations do not undergo scrutiny by the U.S. Food and Drug Administration. Therefore, women are encouraged to speak with their physician before taking any over-the-counter products.

There are also nonprescription strategies for dealing with the greater postmenopausal risks of heart disease, osteoporosis and Alzheimer’s. These include:

  • Weight Management - Achieve and maintain a healthy weight.
  • Quit Smoking - Smoking increases bone loss, probably because it decreases a woman’s production of estrogen and reduces the body’s ability to absorb calcium.
  • Healthy Diet - Women should eat plenty of whole-grain products, vegetables and fruits. They should choose foods that are low in fat and cholesterol and get enough of the vitamins and minerals that are good for their heart and bones.
  • Regular Exercise - Women should try to get at least 30 minutes of exercise on most days of the week. Weight-bearing exercises such as walking, running or dancing can help strengthen bones and reduce the risk of osteoporosis. In addition, exercise may help control weight and it has benefits for the heart.  
  • Limit Alcohol Intake - Women should not have more than one alcoholic drink a day.
  • Stay Mentally Active - by attending community lectures, doing crossword puzzles, reading the newspaper, spending time with friends/family, volunteering in the community and watching the news.
  • Doctor’s Help - Talk with a physician about taking vitamin/mineral supplements for optimum health of the heart and bones, including calcium and vitamin D supplements to help prevent osteoporosis.

Regardless of which strategies are chosen, it is important for all women to get regular screening tests including a blood pressure check, bone density test, cholesterol screening/lipid profile, height measurement, Pap smear, and vision tests done on a regular basis.

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