May 8, 2007
Women who use hormone therapy before the age of 65 could cut their risk of developing Alzheimer's disease, a new report shows. The findings, presented at the 59th Annual Meeting of the American Academy of Neurology in Boston, suggest that use of estrogen therapy may have benefits for the brain in younger postmenopausal women.
The use of the female hormones estrogen and progesterone to treat hot flashes and other symptoms of menopause has been cautioned in recent years. This warning is based on the discovery of potential risks, including an increased risk of breast cancer and strokes. In addition, there is evidence that hormone replacement therapy (HRT) is either ineffective or less effective than previously thought at reducing the risk of heart disease and bone fractures.
Previous research has shown that HRT actually increases the risk of Alzheimer's disease in older women, aged 65 and up, and an increased risk of Alzheimer's disease is now listed on the drug's warning label. This study, however, focused on women who began HRT before age 65.
What the Study Showed
This latest study was part of the Women's Health Initiative Memory Study, which is part of the Women's Health Initiative (WHI), one of the largest U.S. prevention studies of postmenopausal women. The study looked at prior hormone use in 7,153 healthy women ages 65 to 79, before they enrolled in the study. Researchers followed the women's memory and cognitive health over an average of five years.
In that time, 106 of the women developed Alzheimer's disease or another form of dementia. The study found that women who used HRT before the age of 65, before they enrolled in the study, were nearly 50 percent less likely to develop Alzheimer's disease or dementia than women who did not use hormone therapy before that age.
Benefits and Risks
While this latest analysis suggests possible benefits of HRT when it is started by younger postmenopausal women, the effects of estrogen on the brain are still not well understood. Prior studies have shown that women who start hormone therapy after the age of 65 have roughly a 50-percent increased risk of developing dementia. The risk jumped to nearly double for women using estrogen-plus-progestin hormone therapy.
"Further studies are needed to support these findings and learn more about how hormone therapy affects the long-term cognitive health of women who begin use before age 65," said study author Victor W. Henderson, of Stanford University.
Women should discuss the possible benefits and risks with their doctors. Experts generally caution women to use the lowest possible dose for the shortest possible time. However, as with most drugs, even low doses may carry some risks.
Victor W. Henderson, Mark A. Espeland, Patricia E. Hogan, Stephen R. Rapp, et al: "Prior Use of Homrone Therapy and Incident Alzheimer's Disease in the Women's Health Initiative." Presented at the 59th Annual Meeting of the American Academy of Neurology, May 2, 2007.