HRT could cut Alzheimer's risk in some women - early study

Hormone replacement therapy (HRT) could reduce the risk of Alzheimer's disease among some higher-risk women, researchers say data has suggested.

About a quarter of women in the UK are thought to carry a gene called APOE4, which is known to increase the risk of Alzheimer's disease.

The new, early, research found HRT - which can help control menopause symptoms - was associated with better memory and larger brain volumes for those with the gene.

The researchers said it was too early to say for sure whether HRT reduced dementia risk in women, but the results highlighted its potential importance.

The research was an "observational study" rather than a clinical trial.

And it did not measure whether the women it looked at went on to develop dementia.

Alzheimer's Research UK said the findings were encouraging. but that more and larger studies were needed to help understand the link between HRT and changes to the brain.

The study, led by Professor Anne-Marie Minihane, from UEA's Norwich Medical School, with Professor Craig Ritchie at the University of Edinburgh, was published in in the Alzheimer's Research & Therapy journal.

It looked at data from 1,178 women involved in the European Prevention of Alzheimer's Dementia initiative, which studies participants' brain health over time.

All women who took part in the European initiative were over 50 and had no dementia diagnosis when joining it.

This study then looked at results of cognitive tests and brain volumes as recorded by MRI scans.

Dr Rasha Saleh, from UEA's Norwich Medical School. said the findings suggested HRT use was associated with "better memory and larger brain volumes" among the APOE4 gene carriers.

If confirmed in a clinical trial, she said, the effects of HRT would "equate to a brain age that is several years younger".

Prof Minihane said the results of the study were a "very nice finding" that would encourage them to run further studies.

The next stage will be to go on to a clinical trial, she said.

"We'll recruit people who are E4 and non-E4," she told BBC Radio 4's Today programme.

"Put women on HRT, follow them up, study them in quite a lot of detail, and hopefully that will provide us with a definitive answer as to whether HRT is a really effective therapy in women who carry this E4 gene."

She added: "The other major news I suppose was that the earlier the better - that HRT use seemed to be particularly beneficial in women who started it during the perimenopausal or early post-menopausal period."

Dr Sara Imarisio, head of strategic initiatives at the Alzheimer's Research UK, said the study provided evidence that HRT could have some cognitive benefits, but the findings needed to be confirmed with trials that directly tested it.

"The next step is to investigate this in more detail. Importantly, this study didn't measure whether women went on to develop dementia.

"So, its findings need to be confirmed, first in trials that directly test whether giving HRT affects women's cognitive abilities and changes in their brain, particularly carriers of the APOE4 gene.

"This will then help pave the way for finding possible interventions, for example clinical trials to see if it could eventually prevent dementia, and to help understand why dementia disproportionately affects women in the UK."

Alzheimer's Society's associate director of research Dr Richard Oakley also said more studies were needed.

He said: "Studies of this kind are important as they hint at a link between HRT and the changes to the brain.

"We need more studies, on a larger scale, to better understand this link."

Alzheimer's is more common in women than in men - almost two thirds of Alzheimer's patients in the UK are women.

Although the APOE4 gene is known to increase the risk of Alzheimer's disease, people with the gene will not necessarily develop the condition.