TUESDAY, June 22, 2004 (HealthDayNews) -- Hormone therapy does not prevent dementia and may, in fact, even raise the risk in older, postmenopausal women, new research says.
"We did not find any protective effect of hormone therapy, and there was a trend towards an increased risk of dementia," said Claudine Legault, second author of the new study and director of the Women's Health Center of Excellence at Wake Forest University in Winston-Salem, N.C.
The findings, from the Women's Health Initiative Memory Study (WHIMS), appear in the June 23/30 issue of the Journal of the American Medical Association.
WHIMS was established to look at whether hormone therapy, either estrogen alone or estrogen plus progestin, could reduce the risk of dementia in women aged 65 to 79. The WHIMS is part of the larger Women's Health Initiative (WHI), which looked at the effect of hormone therapy on a variety of health outcomes. The estrogen plus progestin arm of the WHI was ended in July 2002 when it became clear that women taking hormones were having more serious side effects. The estrogen-only arm was terminated on Feb. 29, 2004, because of an excess risk of stroke in women taking active hormones.
This study looked at the effects of estrogen alone (Premarin) or estrogen plus progestin (Prempro) in 7,479 women aged 65 to 79. All of the 2,947 women on Premarin had had a hysterectomy. The women were divided into those with probable dementia, those with mild cognitive impairment, and those with no dementia.
Compared to the placebo group, women in the estrogen group had a 34 percent higher risk of being diagnosed with mild cognitive impairment. This increased risk was not considered to be significant. Women on estrogen had a 38 percent greater risk of having either mild cognitive impairment or probable dementia, compared to women in the placebo group.
Outside experts are careful to point out, however, that this study does not pertain to all women or to all hormones.
"This is not a study about women. This is about older women, so this cannot be extrapolated to women who have recently undergone menopause who want to go on hormone therapy, whether it be short term or long term," said Dr. Alan M. Altman, an assistant professor of obstetrics, gynecology, and reproductive biology at Harvard Medical School. Altman was not involved in the research.
This also does not mean that hormone therapy doesn't have a place. "It's clear that use of hormones to prevent dementia or cognitive decline in women 65 or older is not recommended," Dr. Gary Stiles, executive vice president and chief medical officer at Wyeth Pharmaceuticals, said during a news teleconference Monday. Wyeth makes Premarin and Prempro.
"The most appropriate reason that women initiate the therapy is for symptomatic relief of menopausal symptoms, and that was not studied in this study," Stiles said. "We believe that these drugs have their appropriate use."
A second set of findings appearing in the same issue of the journal looked at the effect of hormone therapy on overall cognition functioning. Here, women 65 years or older taking estrogen had a slightly lower cognitive function than women on placebo.
The findings still leave several questions unresolved, including whether there might be a benefit to starting therapy earlier and whether different products and different doses might have a different effect.
Stiles said that the study was started several years ago and the results may not "apply to how medicine is currently practiced." For one thing, doses are lower than used in the study, and women tend to be younger.
For Legault, the findings simply bolster the FDA's recommendations. "The FDA's advice to take the lowest doses for the shortest time required are not necessarily out of range," she said. "Women should talk to their physician and really discuss the entire health picture, because it really depends on family history and their personal history."
"These studies further support last year's recommendations that menopausal hormone therapy should not be used to prevent cognitive decline or dementia in older postmenopausal women," Dr. Judith A. Salerno, deputy director of the National Institute on Aging, said in a statement.
For Altman, however, the findings appear to have little relevance for women who have recently undergone menopause. In his view, the older women tracked in the study "have little business being on hormones. This study doesn't impact any of the patients I see, who come to me early in their 50s -- whether symptomatic or not -- to discuss hormone therapy."
For more on WHIMS, visit Wake Forest University.