NEW YORK (Reuters Health) - Hormone replacement therapy during the early stages of menopause - typically around age 50 - doesn't hurt or help brain function, according to a new study.
Researchers found that women between the ages of 50 and 55 years old who took estrogen or estrogen with progesterone performed just as well on tests that measure memory problems as women of the same age who took a placebo.
"Our findings are that we didn't see any long term impact on cognitive function," said Mark Espeland, the study's lead author, from the Wake Forest School of Medicine in Winston-Salem, North Carolina.
Previous studies had found that women 65 years old and older suffered lasting memory problems when they used hormone therapy to treat symptoms of menopause, such as hot flashes, vaginal dryness and trouble sleeping.
Imaging tests even found that the brains of those older women assigned to hormone therapy had become smaller, compared to those who took a placebo.
Currently, the government-backed U.S. Preventive Services Task Force recommends that postmenopausal women avoid hormone replacement therapy due to increased risks of heart disease, stroke, breast cancer and dementia.
Some research, however, has suggested there may be a "window of opportunity" when women first enter menopause that allows the safe use of hormones to possibly decrease their risk of conditions such as heart disease. What the effects would be on younger women's brains, however, has been unclear.
For the new study, Espeland and his colleagues used data on 1,326 women between the ages of 50 and 55 in the Women's Health Initiative Memory Study to see whether taking estrogen or estrogen and progesterone led to any problems or benefits in brain health.
The women were assigned to take estrogen, estrogen and progesterone or a placebo for about seven years at the beginning of the study between 1996 and 1999. They were then followed for about the next 14 years.
During the follow-up period, the women were asked 14 questions that measured their cognitive abilities during phone interviews.
Overall, all groups scored about a 38 on a scale from zero to 50 - with lower scores signaling more memory problems.
There was also no difference between the groups on several other scales that measured - among other things - attention and working memory.
Francine Grodstein, who wrote an editorial accompany the new study in JAMA Internal Medicine, told Reuters Health the findings are primarily reassuring.
"So for (younger) women who really need hormone therapy to treat menopause symptoms… this study didn't find hormone therapy had the amount of harm as it did for older women," said Grodstein, an associate professor of medicine at Brigham and Women's Hospital in Boston.
Espeland told Reuters Health there could be a few possible explanations for the difference between older and younger women using hormone replacement therapy.
One possible explanation could be that older women already have more memory problems and hormone therapy accelerates the decline. It could also be that a woman's brain adapts to lower levels of hormones after menopause and hormone therapy disrupts that process.
The new study, however, may not have had enough participants to measure any moderate benefits from taking hormone therapy during the early stages of menopause, said Grodstein.
"One study is not going to tell us everything," she said.
But, Espeland noted, the researchers continue to follow these women for more information.