Research suggests that hormone replacement therapy may help prevent Alzheimer’s disease in the millions of women at risk of developing the condition.
Dementia is one of the biggest health threats in the world. The number of people with the condition worldwide is set to nearly triple to 153 million by 2050, and experts have warned it is a major and rapidly growing threat to the health and social care systems of the future in every community, country and continent.
Nearly two out of three people with Alzheimer’s disease are female, and about a quarter of women in the UK alone carry a gene called APOE4, which is the strongest risk factor gene for the disease.
A team of researchers from the University of East Anglia (UEA) and the University of Edinburgh has found evidence of the “potential importance” of hormone replacement therapy (HRT) in reducing the risk of Alzheimer’s disease in women who carry the APOE4 gene. The study was published in the journal Alzheimer’s Research & Therapy.
Although they stressed that they couldn’t say with certainty that HRT reduces risk in women, the findings were “really important” amid the limited drug options for dementia and the desperate need for new treatments.
Researchers found that HRT, which helps control menopausal symptoms, is associated with better memory and cognitive function and larger brain volume later in life in women with the APOE4 gene.
Professor Michael Hornberger, from UEA’s Norwich Medical School, said: “It is too early to say with certainty that HRT reduces the risk of dementia in women, but our findings highlight the potential importance of HRT and personalized medicine in reducing the risk of dementia.” Alzheimer’s disease.
The next phase of this research will be an intervention trial to confirm the effect of starting HRT early on cognition and brain health. It will also be important to analyze which types of HRT are most beneficial.”
In the study, researchers found that HRT was most effective when given during perimenopause — when symptoms build up months or years before menstruation stops — and can lead to brains that are several years younger.
Professor Anne-Marie Minihan, from Norwich Medical School, and co-leader of the study, said: “We know that 25% of women in the UK carry the APOE4 gene and that nearly two-thirds of Alzheimer’s patients are women.
In addition to living longer, the reason for the higher female prevalence is thought to be related to the effects of menopause and the influence of the genetic risk factor APOE4 which is greater in women.
“We wanted to find out whether HRT could prevent cognitive decline in APOE4 carriers at risk.”
The team analyzed data from 1,178 women participating in European prevention of Alzheimer’s dementia which was created to study participants’ brain health over time.
The project, which spans 10 countries, tracked the brains of 1,906 people over 50 who did not have dementia at the start of the study. For the new research, experts looked at cognitive test results and brain volumes as recorded on MRI scans.
The results showed that APOE4 carriers who also used HRT had better cognition and higher brain volumes than people without HRT and non-APOE4 carriers.
Dr Rasha Saleh, from Norwich Medical School, said: “We found that use of HRT is associated with better memory and greater brain volume among gene carriers at risk of APOE4. The associations were particularly clear when HRT was introduced early – during the transition to menopause. , known as amenorrhea.
“This is really important because there have been very limited drug options for Alzheimer’s disease for 20 years and new treatments are urgently needed. The effects of HRT in this observational study, if confirmed in an intervention trial, would equate to a brain lifespan several years younger.”
The team did not look at cases of dementia, Minihan said, but cognitive functioning and reduced brain volume are predictive of future dementia risk.
The risk of developing Alzheimer’s disease and other types of dementia increases with age, affecting an estimated one in 14 people over the age of 65 and one in six people over the age of 80. Inheriting APOE4 does not mean that someone will definitely develop the condition.
Study leader Professor Craig Ritchie, from the University of Edinburgh, said the study “highlights the need to challenge many assumptions about early-onset Alzheimer’s disease and its treatment, particularly when looking at women’s brain health”.
He added, “The effect on cognition and brain changes on MRI supports the idea that HRT has a measurable benefit. However, these initial findings need to be replicated in other populations.”
Dr Sara Imaricio, head of strategic initiatives at Alzheimer’s Research UK, said the findings were “encouraging” but needed confirmation in further studies.
“They provide evidence that HRT can have some cognitive benefits, particularly in women who carry the APOE4 Alzheimer’s disease risk gene,” she said. “The next step is to investigate this in more detail.”
If the new findings are later confirmed, Imaricio said, they could pave the way for clinical trials to see if HRT can eventually prevent dementia.
Dr. Richard Oakley, associate director of research at the Alzheimer’s Society, said: “Studies of this nature are important because they suggest a link between HRT and changes in the brain. We need more studies, on a larger scale, to better understand this link.”