While the two studies offer differing explanations for the postmenopausal increase in blood pressure, they lend new insights into how women's cardiovascular risk changes after menopause—and the best approaches to managing those risks.
Study Assesses Impact of Body Mass Index on Blood Pressure in Menopause
In a study led by Dr. Renata Cifkova of the Institute for Clinical and Experimental Medicine in Prague, Czech Republic, detailed blood pressure measurements were made in about 900 women aged 45 to 54. The women were classified as being premenopausal, late in the menopausal transition, or postmenopausal. The relationship between stage of menopause and blood pressure was analyzed, taking into account a wide range of other factors.
After adjustment for the effects of age, there was no relationship between blood pressure and menopausal status—blood pressure levels were similar for women who were premenopausal, going through menopause, or postmenopausal. Menopausal status also had no effect on the risk of high blood pressure (hypertension).
On further analysis, the factor most strongly related to blood pressure was the women's body mass index (BMI)—a standard measure of body fatness, which tends to increase with age. "The rise in blood pressure after the menopause appeared to be due to increased BMI, rather than to ovarian failure per se," reports Dr. Cifkova and colleagues.
Second Study Evaluates Blood Pressure Values in Women From 18 to 70
A second study, led by Dr. Edoardo Casiglia of University of Padova, Italy, included more than 9,000 women ranging in age from 18 to 70. Absolute blood pressure levels were higher for menopausal women than for fertile (premenopausal) women. Other potential cardiovascular risk factors were also greater in menopausal women.
However, as in the Czech study, the relationship between menopause and blood pressure was no longer significant after adjustment for age. Apparent menopause-related differences in several other risk factors—including BMI—also disappeared after adjustment for age.
On long-term follow-up, menopausal women had greater increases in blood pressure and cardiovascular disease risk, compared to fertile women. Again, however, the differences were no longer present after adjustment for age. "Menopausal women seem to have higher BP values and worse risk profile than the fertile ones, but this is simply due to their older age," according to the researchers.
Reduced Levels of Oestrogen Do Not Increase Cardiovascular Risk
Increases in blood pressure likely contribute to the increased risk of cardiovascular disease after menopause. It has sometimes assumed that the rise in blood pressure results from the drop in levels of the hormone oestrogen after menopause, and thus that menopause "makes women similar to men" in terms of cardiovascular risk.
The two new studies agree that menopause itself does not cause increased blood pressure. The Czech researchers think that increases in body weight in older women are the most important factor. If so, then weight loss and other lifestyle changes in might help to prevent increases in blood pressure —and thus reduce cardiovascular risk—in women after menopause.
The Italian researchers believe that older age is the key contributor to increases in blood pressure and other cardiovascular risk factors after menopause. In any case, the postmenopausal rise in blood pressure doesn't appear to result from menopause-related drops in oestrogen level. This may help to explain why studies of hormone replacement therapy to prevent cardiovascular disease didn't work, "simply put, the target of therapy was wrong," Dr. Casiglia and colleagues conclude.
About Hypertension (High Blood Pressure)
High blood pressure is a disorder in which the pressure in the arteries is too high. The medical term for blood pressure that remains high over time is "hypertension". An estimated 600 million people affected worldwide (Cardiovascular Diseases - Prevention and Control, WHO, 2001-2002) Hypertension, is dangerous because it makes the heart work harder to pump blood to the body and it contributes to hardening of the arteries or atherosclerosis and the development of heart failure.Hypertension is classified as either primary (or essential) hypertension or secondary hypertension.
- Primary hypertension has no specific origin but is strongly associated with lifestyle. It is responsible for 90 to 95 percent of diagnosed hypertension and is treated with stress management, changes in diet, increased physical activity, and medication (if needed).
- Secondary hypertension is responsible for 5 to 10 percent of diagnosed hypertension. It is caused by a preexisting medical condition such as congestive heart failure, kidney failure (renal hypertension), liver failure, or damage to the endocrine (hormone) system (e.g., pheochromocytoma, a rare type of tumor of the adrenal glands that causes production of excessive amounts of adrenal hormones, which cause high blood pressure). Secondary hypertension may be cured if its cause is dealt with.
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- Chest pain
- Difficulty breathing
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