Aging: Can Hormones Prevent Aging? (cont.)

But estrogen also is a good example of why it is important to wait until researchers have discovered both the benefits and risks of a hormone before it becomes widely used. While some women are helped by estrogen during and after menopause, others are placed at higher risk for certain diseases if they take it.

Early studies suggested menopausal hormone therapy could lower the risk for heart disease (the number-one killer of women in the United States) in postmenopausal women. But results from the Women's Health Initiative (WHI), an important study of menopausal hormone therapy funded by the National Institutes of Health, now suggests that using estrogen with or without a progestin after menopause does not protect postmenopausal women (ages 50 and older) from heart disease and may even increase their risk. In 2002, WHI scientists reported that using estrogen plus progestin actually elevates some women's chance of developing heart disease, stroke, blood clots, and breast cancer. But they also found health benefits-not as many hip fractures and fewer cases of colorectal cancer. In 2004, the same scientists reported that using estrogen alone increased a woman's risk of stroke and blood clots, but protected women from hip fractures.

Some studies suggest that estrogen may protect against Alzheimer's disease, but this has not yet been proven. In fact, in 2003, researchers in a WHI substudy, the WHI Memory Study (WHIMS) reported that women age 65 and older taking a combination of estrogen plus progestin were at twice the risk of developing dementia as women not taking any hormones. Again in 2004, these WHIMS scientists reported that using estrogen alone could increase the risk of developing dementia in women age 65 and older compared to women not taking any hormones.

As a result of these studies, experts have concluded that the health risks of using menopausal hormone therapy may be greater than the health benefits. These risks may differ between women who have menopausal symptoms and those who don't. Nevertheless, the FDA has stated that women who want to use menopausal hormone therapy to control the symptoms of menopause should do so at the lowest effective dose for the shortest time needed.

But the question of these greater risks is still an important public health issue. Even small increases, when millions of women are using menopausal hormone therapy, could mean many more cases of heart disease, stroke, blood clots, and breast cancer.

So the decision whether to take estrogen is now far more complex and difficult than ever before. Questions about menopausal hormone therapy remain: Would using a different estrogen and/or progestin or another dose change the risks? Would the results be different if the hormones were given as a patch or cream, rather than a pill? Would taking the progestin less often be as effective and safe? Does starting menopausal hormone therapy around the time of menopause compared to beginning years later change the risks? Can we predict which women will benefit or be harmed by using menopausal hormone therapy? As answers to these and other questions are found, women and their doctors should frequently review the pros and cons of menopausal hormone therapy in order to make an informed choice based on a realistic assessment of personal risks and benefits.

Many Questions, Few Answers

The NIA sponsors research that will reveal more about the risks and benefits of hormone therapies and supplements. One goal is to determine whether DHEA, melatonin, and other hormonal supplements improve the health of older people, have no effect, or are actually harmful.

It is important to remember that these studies may not yield immediate or final answers, especially in the cases of DHEA, melatonin, and hGH, since research on these supplements is fairly new. Some of these studies, for example, may simply provide researchers with more information about what kinds of questions they should ask in their next studies. Research is a step-by-step process, and larger studies may be needed to give more definitive answers.

Until more is known about DHEA, melatonin, and hGH, consumers should view them with a good deal of caution and doubt. Despite what advertisements or stories in the media may claim, hormone supplements have not been proven to prevent aging. Some harmful side effects already have been discovered and additional research may uncover others.

More is known about estrogen, progesterone, and testosterone, and people with genuine deficiencies of these hormones should consult with their doctors about supplements. Meanwhile, people who choose to take any hormone supplement without a doctor's supervision should be aware that these supplements appear to have few clear-cut benefits for healthy individuals, and no proven influence on the aging process.

Source: National Institute of Aging, National Institutes of Health

Last Editorial Review: 3/23/2006