Hormone therapy may reduce risk of Alzheimer's in some women, study finds

• Hormone therapy before menopause could help women with a higher risk of Alzheimer's protect their brains.
• A new study suggests the treatment is linked to better memory, comparable to a younger brain.

Hormone replacement therapy could help women who have a genetic risk factor for Alzheimer's disease keep their brains healthy as they age, new research suggests.

Women make up two-thirds of Alzheimer's patients, studies show. That is, in part, because they tend to live longer, but researchers also believe menopause plays a role as sharp declines in hormones like estrogen can affect the brain. Genetics, in particular a gene called APOE4, can also be a major risk factor.

Some previous research found that early hormone replacement therapy can help stave off brain aging and diseases like Alzheimer's, as estrogen levels begin to drop leading up to menopause.

The new study, published January 9 in Alzheimer's Research & Therapy, suggests that the hormone treatment could be especially beneficial for women with the genetic risk factor for Alzheimer's.

The study researchers, from the University of Anglia and University of Edinburgh in the UK, looked at data from 1,178 European women over age 50, who didn't have any form of dementia. The data compared participants' brain health over time using measurements such as MRI scans and cognitive tests

The researchers found that hormone therapy was linked to better memory and larger brain volume in women with the APOE4 genetic risk factor for Alzheimer's. The results would be equivalent to a brain several years younger, according to Dr. Rasha Saleh, co-author of the study and senior research associate at the University of East Anglia's Norwich Medical School.

"This is really important because there have been very limited drug options for Alzheimer's disease for 20 years and there is an urgent need for new treatments," Saleh said in a press release.

The treatment was most effective when participants started hormone therapy during perimenopause, the onset of symptoms leading up to menopause, the data suggested.

However, the study was observational — the findings need to be confirmed in a clinical trial, Saleh said. Further studies could confirm whether the results would hold true for a broader population, and take into account factors like the age of starting menopause.

While the results of the study are promising for potential benefits from hormone therapy, more research is needed to know whether the treatment can prevent dementia, for whom, and what types of therapy might be best, the researchers wrote.