Estrogen Plus Progestin Doubles Dementia Risk in Women 65 and Over, WHIMS Study Shows

BUFFALO, N.Y. -- A national study involving 151 women from Western New York, conducted to assess the effect of hormone therapy on dementia and mild cognitive impairment, has shown that women 65 and over who take combined estrogen and progestin may double their risk of developing dementia.

The Women's Health Initiative Memory Study (WHIMS) is a sub-study of the Women's Health Initiative (WHI). Jean Wactawski-Wende, Ph.D., assistant professor of social and preventive medicine and gynecology and obstetrics and co-director of UB's WHI Vanguard Center, is one of the study authors.

Results of the WHIMS study were posted on the Journal of the American Medical Association Web site today (http://jama.ama-assn.org/) and will appear in this week's issue of the journal.

"For postmenopausal women age 65 and over, estrogen plus progestin is not a viable option for prevention of cognitive impairment and, in fact, doubles the risk of developing dementia," said Wactawski-Wende. The WHIMS study included only women 65 and over, so the effect of hormone therapy on cognition in younger women hasn't been determined, she said.

While the risk of dementia in the population at large is doubled, the risk to each individual woman is relatively small, said Wactawski-Wende. "For every 10,000 women 65 or over who took estrogen plus progestin, 45 women developed dementia per year, compared to 22 cases of dementia in those taking placebo. This represents an additional 23 cases of dementia per year in every 10,000 women treated."

Wactawski-Wende said women should discuss these finding with their health-care providers, adding that the results of this study should be considered in the overall balance of risks and benefits of estrogen plus progestin for each woman.

The study involved 4,532 postmenopausal women age 65 and over. The women were followed for 4.2 years at 39 WHI clinical centers around the U.S. Half the women took a daily dose of the drug Prempro, a combination of estrogen and progestin, and half took a placebo.

This arm of the WHI study was terminated in July 2002, along with the WHI study assessing the effect of hormone therapy on cardiovascular disease in postmenopausal women, when the risks were found to outweigh the benefits. The data from the memory study had not been analyzed fully at that time.

The WHIMS study arm involving women who are taking estrogen alone, without progestin, is ongoing. Results of that study will be available by 2005.