Harvard Women's Health Watch

By the way, doctor: Does hormone therapy cause dementia?

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.

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