Does Hormone Therapy Cause Dementia?

Celeste Robb-Nicholson, M.D.

Q. The Women's Health Initiative found that hormone therapy wasn't helpful for avoiding dementia; there was some suggestion that it might even cause cognitive problems. Am I at risk for dementia by continuing hormone therapy?

A. You're right about the results of the Women's Health Initiative Memory Study (WHIMS), the largest clinical trial to date of the effects of hormone therapy (HT) on cognitive function and dementia. Women ages 65 to 79 took HT (estrogen alone or estrogen combined with a progestin) or a placebo. After four to five years, the researchers found that taking HT didn't improve cognitive function. Moreover, the women who took combined estrogen and progestin were twice as likely as the placebo takers to develop dementia.

These findings don't square with animal and laboratory studies suggesting a favorable effect of estrogen on cognitive function. And there's strong biological evidence that estrogen is important for brain function in women. Estrogen receptors are found throughout the brain, and many interactions take place between the brain and the reproductive endocrine system. Some research suggests that ovary removal during hysterectomy increases the risk of cognitive problems, presumably due to the loss of estrogen.

So what accounts for the WHIMS results? Some researchers think the problem is in the timing; they suggest that HT is more likely to benefit the brain if it's started in early menopause. A five-year clinical trial called the Kronos Early Estrogen Prevention Study (KEEPS) is now addressing this question. Results are expected in 2011.

Based on what we know right now, HT won't improve your thinking or stave off dementia. But could it increase your risk for cognitive problems? Here the evidence is less compelling. We do know that taking HT increases the risk for several serious conditions, including blood clots, stroke, heart attack, and breast cancer (when estrogen is combined with a progestin). Unless you have burdensome hot flashes or vaginal atrophy that can't be controlled any other way, I suggest that you taper off HT, which is recommended only for the short-term relief of such symptoms.

There are several non-hormonal, risk-free strategies that may help your memory and thinking, including these: get regular exercise; keep learning -- through work, hobbies, or pursuits such as reading; get enough sleep; and review your medications, to make sure you're not taking anything that could interfere with your thinking.

There is some evidence to suggest that hormone therapy (HT) used during menopause may be associated with an increased risk of dementia. However, the evidence is not conclusive and the relationship between HT and dementia is complex.

Some studies have found that women who use HT for a prolonged period of time, particularly those who start using it many years after menopause, have an increased risk of developing dementia. However, other studies have found no association between HT and dementia, or have even suggested that HT may have a protective effect against cognitive decline.

It's important to note that the findings are inconsistent and more research is needed to fully understand the relationship between HT and dementia. The best approach for an individual woman will depend on her individual medical history, risk factors, and the type and dose of hormone therapy being used. Women who are considering hormone therapy should discuss the potential risks and benefits with their doctor.

Hormone Therapy

Hormone therapy (HT) is a treatment that replaces or supplements hormones in the body. Hormone therapy is commonly used to relieve symptoms of menopause, such as hot flashes, night sweats, and vaginal dryness. It can also be used to treat other conditions, such as osteoporosis and endometriosis.

HT is usually delivered as a pill, skin patch, gel, cream, or vaginal ring. It can contain either estrogen alone or a combination of estrogen and progestin, depending on the individual's needs and medical history. Women who have had a hysterectomy may take estrogen alone, while women who still have their uterus need to take a combination of estrogen and progestin to reduce the risk of endometrial cancer.

The use of HT is a personal decision that should be made in consultation with a doctor. Hormone therapy can have both benefits and risks, and the choice to use HT will depend on a woman's individual medical history, risk factors, and symptoms. Women who are considering HT should discuss the potential benefits and risks with their doctor to determine the best approach for their individual needs.

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