Research suggests that a quarter of the millions of British women taking a common menopause treatment could be at increased risk of developing Alzheimer’s.
Hormone replacement therapy (HRT), which uses synthetic versions of female sex hormones such as estrogen to replace levels lost in middle age, has gained popularity in recent years and is now taken by 2.6 million women.
Experts say the growing demand is partly because celebrities like Davina McCall praise the benefits, claiming the drug does everything from boosting sex drive to sharpening memory.
But now, scientists at Liverpool John Moores University have found that women with a particular genetic trait who take HRT have 60 per cent higher levels of a molecule linked to Alzheimer’s disease, compared to genetically vulnerable women who do not. they receive the treatment.
The gene, called APOE e4, is relatively common, found in about one in four people.
Previous research has found that those with one copy of the gene are two to three times more likely to develop Alzheimer’s, although this can increase up to 10 times for those with two copies in their genetic makeup.
Alzheimer’s is the leading cause of dementia, a disorder that deprives people of their independence and is on the rise in Britain.
The authors of the new study said their research, although in its early stages, could have implications for deciding which women take HRT in the future.
Dr Davide Bruno, a neuropsychology expert who led the study, said: If our results are confirmed, they would warn against the use of HRT in women at high risk of Alzheimer’s due to a genetic susceptibility.
Davina MCCall is credited with inspiring thousands of women to try HRT after documenting her own experience of menopause, dubbed the “Davina effect.”
The latest NHS data shows that a record 2.6 million women in England took HRT last year, up 12 per cent from 2.3 million the previous year and double the number in 2018/19.
“There is still a lot we don’t know, but it may be prudent to test women for the presence of the APOE e4 variant before giving them HRT, at least until more knowledge is gained on this issue.”
In the study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, experts analyzed samples of cerebrospinal fluid, the fluid that protects the brain and spine, from 136 women.
These women, who had an average age of 66, had no cognitive problems at the time the samples were taken.
Scientists looked for a natural substance known to be a precursor to the brain plaques and tangles associated with Alzheimer’s.
They compared outcomes between women taking and not taking HRT, as well as between those with the APOE e4 variant and those without it.
Women taking HRT without the APOE e4 variant, as well as those with the gene but not on HRT, had similar levels of this molecule.
But in women who combined HRT and the APOE e4 variant, levels of this molecule were more than 60 percent higher than the baseline level.
Exactly how HRT can lead to an increased risk of dementia is not yet understood.
Previous research on the topic has yielded mixed results. Some studies, involving more than 400,000 women, found that HRT reduced the risk of dementia.
However, other studies involving 50,000 women found the opposite.
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss.
It is currently believed that around 900,000 Britons suffer from this memory-robbing disorder. But scientists at University College London estimate this figure will rise to 1.7 million within two decades as people live longer. It marks a 40 percent increase from the previous forecast in 2017.
Adding to the confusion is the fact that estrogen is considered good for brain health. Its absence explains why “brain fog” is a symptom of menopause.
Therefore, experts do not yet understand why HRT, which replaces this lost estrogen, would increase the risk of Alzheimer’s in some people.
But Dr. Bruno said one theory was that the hormone could cause more damage to brain cells that are already malfunctioning.
“We think this may be a scenario in which estrogen exposure could be beneficial for healthy neurons, but, conversely, estrogen could worsen the damage in ‘diseased’ neurons,” he said.
The Alzheimer’s Society says the evidence linking HRT to dementia risk is mixed.
The organization says research in this area is confounded by key differences in the studies, for example, the different ages of the women participating.
Additionally, the form of HRT taken (oral, topical, or pessary) varies between studies and it is thought that the type of medication may have a different effect on dementia risk.
The latest NHS data shows that a record 2.6 million women in England took HRT last year, up 12 per cent from 2.3 million the previous year and double the 2018/19 figure.
A recent analysis by the Alzheimer’s Society estimates that the total annual cost of dementia in the UK is £42 billion a year, with families hardest hit.
An aging population means these costs – which include lost income from unpaid carers – will soar to £90 billion over the next 15 years.
Around 944,000 people in the UK are thought to be living with dementia, while in the US the figure is around 7 million.
Alzheimer’s affects approximately six in 10 people with dementia.
Memory problems, thinking and reasoning difficulties, and language problems are common early symptoms of the condition, which then worsen over time.
Analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, compared to 69,178 the previous year, making it the leading cause of death in the country.