A quarter of the millions of British women taking a common menopause treatment could be at increased risk of developing Alzheimer’s, research suggests.
Hormone Replacement Therapy (HRT), which uses synthetic versions of female sex hormones like oestrogen to replace levels lost in mid-life, has soared in popularity in recent years — now taken by 2.6million women.
Experts say the surging demand is partly due to celebrities like Davina McCall hailing the benefits, claiming the medication does everything from boosting sex drive to sharpening memory.
But now scientists from Liverpool John Moores University have found 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 not on the treatment.
Called APOE e4, the gene is relatively common and found in about one in four people.
Previous research has found those with one copy of the gene have double or triple the chance of developing Alzheimer’s, though this can rise to 10-fold for those with two copies in their genetic make-up.
Alzheimer’s is the leading cause of dementia — a memory robbing disorder that strips people of their independence and that is on the rise in Britain.
The authors of the new study said their research, though in its early stages, could have implications for deciding which women take HRT in the future.
Dr Davide Bruno, an expert in neuro-psychology who led the study, said: If our results are confirmed, they would caution against HRT use in women at elevated risk for Alzheimer’s due to genetic susceptibility.
Davina MCCall has been credited with inspiring thousands of women to try HRT after documenting her own experience of the menopause, dubbed the ‘Davina effect’.
The latest NHS data shows a record 2.6million women in England took HRT last year this was up 12 per cent from 2.3million previous year and double the figure for 2018/19
‘There is still a lot we don’t know but it may be prudent to test women for presence of the APOE e4 variant before HRT administration, at least until more knowledge on this matter is acquired.’
In the study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, experts analysed samples of cerebrospinal fluid, the liquid 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 linked to Alzheimer’s.
They compared results between women taking HRT and not, as well as those with the APOE e4 variant and those without it.
Women taking HRT without the APOE e4 variant as well as those with gene but not on HRT had similar levels of this molecule.
But in women where HRT and the APOE e4 variant were combined, levels of this molecule were more than 60 per cent higher than the base level.
How exactly HRT may be leading to increased dementia risk is still not understood.
Previous research on the topic has delivered mixed results. Some studies, involving more than 400,000 women, found HRT reduced dementia risk.
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
Around 900,000 Brits are currently thought to have the memory-robbing disorder. But University College London scientists estimate this will rise to 1.7million within two decades as people live longer. It marks a 40 per cent uptick on the previous forecast in 2017
Adding to the confusion is that oestrogen is considered good for brain health. Its absence explains why ‘brain fog’ is a symptom of the menopause.
Therefore, experts don’t yet understand why HRT, which replaces this lost oestrogen, would increase Alzheimer’s risk in some people.
But Dr Bruno said one theory was that the hormone may cause further damage to cells in the brain that are already malfunctioning.
‘We think this may be a scenario whereby exposure to oestrogen might be beneficial for healthy neurons, but in contrast oestrogen might worsen damage in ‘sick’ neurons,’ he said.
The Alzheimer’s Society say the evidence linking HRT to dementia risk is mixed.
The organisation say research in this area is muddied by key differences in studies — for example, varying ages of the women participating.
Additionally, the form of HRT taken — oral, topical or pessary — varies between studies, and its thought the type of medication can have a differing effect on dementia risk.
The latest NHS data shows a record 2.6million women in England took HRT last year — up 12 per cent from 2.3million previous year and double the figure for 2018/19.
Recent analysis by the Alzheimer’s Society estimates the overall annual cost of the dementia to the UK is £42billion a year, with families bearing the brunt.
An ageing population means these costs – which include lost earnings of unpaid carers – are set to soar to £90billion in the next 15 years.
Around 944,000 in the UK are thought to be living with dementia, while the figure is thought to be around 7million in the US.
Alzheimer’s affects around 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.
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.
